{ "register": "evidence_register_nepal2026", "case": "Nepal 2026 — Bhote Koshi / Trishuli ice-rock slope-failure cascade: rapid ice-rock slope failure, debris avalanche and flash flood — hydraulic mechanism provisional", "evidence_as_of": "2026-09-11", "register_updated": "2026-09-13", "register_update_note_3": "13 Sep 2026: E-047 records a validated negative result — Sentinel-2 spectral indices cannot delineate this turbid channel, so the EO width product is not deliverable from free optical imagery.", "register_update_note_2": "13 Sep 2026, second pass: E-039 telemetry-loss sequence, E-045 seismic-origin-to-warning interval, E-046 Sentinel-2 scene-availability census. Derivations and one catalogue census; no imagery processed, no model re-run.", "register_update_note": "13 Sep 2026: three derivation/observation entries added for the warning lead-time ledger (E-036, E-037, E-038). No new external evidence was sought, no model output changed, and no simulation was re-run.", "previous_evidence_freeze": "2026-09-04", "rules": { "source_tier": [ "near_primary", "primary", "secondary", "tertiary" ], "confidence": [ "High", "Low", "Low-Medium", "Medium", "Qualitative" ], "use": [ "calibration", "corroboration", "excluded", "narrative_only", "scenario_bound", "stage_observational_check", "timing_diagnostic", "timing_reference" ], "observation_dependence": [ "independent", "partially_dependent", "same_event_correlated", "unknown" ], "event_time": "when the physical event or observation occurred (never the publication date)", "published_date": "when the source was published", "human_impact": "casualty, missing-person and displacement figures are excluded and are not recorded", "use_vocabulary": "\"validation\" is not used at this stage; it is reserved for a frozen model architecture evaluated against independent or withheld data. Evidence roles: timing_reference is the T0 anchor the model clock is set by; timing_diagnostic is an observed arrival the model is tested against; stage_observational_check is a measured stage the model is tested against; corroboration is an independent report of the same quantity. Entries carried use=validation before 12 Sep 2026: E-002 -> timing_reference, E-020/E-021/E-025 -> timing_diagnostic, E-022 -> stage_observational_check, E-023/E-024 -> corroboration." }, "entries": [ { "id": "E-001", "item": "Event date", "value": "2026-08-26", "unit": "date", "source_url": "https://www.moha.gov.np/en/post/ha-ra-tha-ka-apa-l-11", "publisher": "Government of Nepal, Ministry of Home Affairs", "published_date": "2026-08-26", "event_time": "2026-08-26", "accessed_date": "2026-09-03", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "date only", "use": "narrative_only", "notes": "Corroborated by USGS ComCat origin (E-002). Carried from the 4 Sep 2026 evidence freeze; not re-fetched in the 11 Sep sweep.", "sweep_ref": null }, { "id": "E-002", "item": "ComCat us7000tbwb origin time", "value": "2026-08-26T02:52:10Z (= 2026-08-26 08:37:10 NPT, UTC+05:45)", "unit": "UTC", "source_url": "https://earthquake.usgs.gov/fdsnws/event/1/query?eventid=us7000tbwb&format=geojson", "publisher": "USGS NEIC (ComCat)", "published_date": "2026-08-26", "event_time": "2026-08-26T02:52:10Z", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "eventtime-error 0.00 s as listed; origin evaluation-status \"preliminary\", review-status \"reviewed\"; epoch ms 1787712730000.", "use": "timing_reference", "notes": "Used as model T0 (slope failure) for the timing checks. ComCat event type 'landslide', reviewed; initially reported as an M4.4 earthquake and reclassified.", "observation_dependence": "independent", "verbatim_quote": "\"eventtime\": \"2026-08-26T02:52:10.000Z\"", "sweep_ref": "sweep-2026-09-11/A_entries.json[14]" }, { "id": "E-003", "item": "ComCat us7000tbwb magnitude", "value": "5.2 (magType ms_vx; magnitude-error 0.09; 26 stations)", "unit": "magnitude", "source_url": "https://earthquake.usgs.gov/fdsnws/event/1/query?eventid=us7000tbwb&format=geojson", "publisher": "USGS NEIC (ComCat)", "published_date": "2026-08-26", "event_time": "2026-08-26T02:52:10Z", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "magnitude-error 0.09", "use": "narrative_only", "notes": "Event initially reported as M4.4 earthquake then reclassified (see next entry).", "verbatim_quote": "\"magnitude\": \"5.2\", \"magnitude-error\": \"0.09\", \"magnitude-num-stations-used\": \"26\", \"magnitude-source\": \"us\", \"magnitude-type\": \"ms_vx\"", "sweep_ref": "sweep-2026-09-11/A_entries.json[15]" }, { "id": "E-004", "item": "ComCat us7000tc90 origin time", "value": "2026-08-26T06:00:35Z (= 2026-08-26 11:45:35 NPT)", "unit": "UTC", "source_url": "https://earthquake.usgs.gov/fdsnws/event/1/query?eventid=us7000tc90&format=geojson", "publisher": "USGS NEIC (ComCat)", "published_date": "2026-08-27", "event_time": "2026-08-26T06:00:35Z", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "eventtime-error 2.87 s; origin evaluation-status \"confirmed\", review-status \"reviewed\".", "use": "narrative_only", "notes": "Second landslide-type signal 3 h 08 min after the first; location fixed to the first event. Physically and temporally distinct from the 28 Aug barrier-lake overflow (E-060).", "verbatim_quote": "\"eventtime\": \"2026-08-26T06:00:35.000Z\", \"eventtime-error\": \"2.87\"", "sweep_ref": "sweep-2026-09-11/A_entries.json[18]" }, { "id": "E-005", "item": "USGS event classification (current page wording, findings as of 8/28/26)", "value": "catastrophic debris flow and flood likely triggered by rapid slope failure involving a glacier", "unit": null, "source_url": "https://web.archive.org/web/20260910230007/https://www.usgs.gov/programs/landslide-hazards/science/2026-nepal-debris-avalanche-and-flash-flood", "publisher": "USGS Landslide Hazards Program", "published_date": "2026-08-27", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "Explicitly preliminary/provisional (\"likely\"); page disclaimer says not final-approved.", "use": "narrative_only", "notes": "Live usgs.gov returned CloudFront 403 / AWS-WAF JS challenge (HTTP 202) to curl and empty content to WebFetch on 2026-09-11; text taken from Internet Archive capture 20260910230007 (id_ raw), saved as A_raw/usgs_page_wb_20260910230007.html. Page title: \"2026 Nepal Debris Avalanche and Flash Flood\". Byline date August 27, 2026. Original URL: https://www.usgs.gov/programs/landslide-hazards/science/2026-nepal-debris-avalanche-and-flash-flood", "verbatim_quote": "On Wednesday morning (local time), 26 August 2026, a catastrophic debris flow and flood was likely triggered by rapid slope failure involving a glacier in Lāṅṭāṇ National Park, Nepal, near the border with China.", "sweep_ref": "sweep-2026-09-11/A_entries.json[0]" }, { "id": "E-006", "item": "USGS event classification (EARLIER wording, findings as of 8/27/26; later revised)", "value": "catastrophic debris flow and flood likely triggered by a glacial collapse", "unit": null, "source_url": "https://web.archive.org/web/20260828065414/https://www.usgs.gov/programs/landslide-hazards/science/2026-nepal-debris-avalanche-and-flash-flood", "publisher": "USGS Landslide Hazards Program", "published_date": "2026-08-27", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Low-Medium", "reported_precision_or_uncertainty": "Superseded wording. Wayback captures show this wording at 20260828065414 and 20260828093717; revised wording present from 20260828200743 onward.", "use": "narrative_only", "notes": "Earlier USGS wording (findings as of 27 Aug), revised on 28 Aug; see E-005.", "verbatim_quote": "On Wednesday morning (local time), 26 August 2026, a catastrophic debris flow and flood was likely triggered by a glacial collapse in Langtang National Park, Nepal, near the border with China.", "sweep_ref": "sweep-2026-09-11/A_entries.json[1]" }, { "id": "E-007", "item": "USGS statement on uncertainty of initiation type (8/28 version)", "value": "unclear whether landslide incorporating part of a glacier or a glacial collapse", "unit": null, "source_url": "https://web.archive.org/web/20260910230007/https://www.usgs.gov/programs/landslide-hazards/science/2026-nepal-debris-avalanche-and-flash-flood", "publisher": "USGS Landslide Hazards Program", "published_date": "2026-08-27", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Qualitative", "reported_precision_or_uncertainty": "Stated as unresolved.", "use": "narrative_only", "notes": "Live usgs.gov returned CloudFront 403 / AWS-WAF JS challenge (HTTP 202) to curl and empty content to WebFetch on 2026-09-11; text taken from Internet Archive capture 20260910230007 (id_ raw), saved as A_raw/usgs_page_wb_20260910230007.html.", "verbatim_quote": "At this time, it is unclear if the initial slope failure was a landslide incorporating part of a glacier or a glacial collapse.", "sweep_ref": "sweep-2026-09-11/A_entries.json[2]" }, { "id": "E-008", "item": "USGS travel distance of debris flow and flood", "value": "approximately 100", "unit": "km", "source_url": "https://web.archive.org/web/20260910230007/https://www.usgs.gov/programs/landslide-hazards/science/2026-nepal-debris-avalanche-and-flash-flood", "publisher": "USGS Landslide Hazards Program", "published_date": "2026-08-27", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "\"approximately\"/\"nearly\" 100 km; ~62 miles. No method or end-point given.", "use": "narrative_only", "notes": "Travel distance is compared only as an internal-consistency check: the modelled distance is censored by the 127.9 km corridor end.", "verbatim_quote": "The debris flow and flood travelled approximately 100 kilometers (approximately 62 miles).", "sweep_ref": "sweep-2026-09-11/A_entries.json[4]" }, { "id": "E-009", "item": "USGS description of flow transformation (mechanism-relevant)", "value": "glacial debris with water and ice melted and entrained material/water in existing channels -> fast-moving far-travelled landslide and flood", "unit": null, "source_url": "https://web.archive.org/web/20260910230007/https://www.usgs.gov/programs/landslide-hazards/science/2026-nepal-debris-avalanche-and-flash-flood", "publisher": "USGS Landslide Hazards Program", "published_date": "2026-08-27", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Qualitative", "reported_precision_or_uncertainty": "Descriptive, preliminary; no mention of channel blockage or dam breach on the page.", "use": "narrative_only", "notes": "Live usgs.gov returned CloudFront 403 / AWS-WAF JS challenge (HTTP 202) to curl and empty content to WebFetch on 2026-09-11; text taken from Internet Archive capture 20260910230007 (id_ raw), saved as A_raw/usgs_page_wb_20260910230007.html. Bears on mechanism: USGS describes direct debris-flow/flood transformation and does not mention a sustained channel blockage.", "verbatim_quote": "The glacial debris contained water and ice that rapidly melted, picking up more material and water as it flowed downslope in the existing stream and river channels, creating a fast-moving, far-traveled landslide and flood laden with boulders and other rubble.", "sweep_ref": "sweep-2026-09-11/A_entries.json[11]" }, { "id": "E-010", "item": "ComCat us7000tbwb location", "value": "lat 28.271, lon 85.515, depth 0 km; place \"55 km NW of Kodari, Nepal\"; location estimated from satellite images", "unit": "degrees", "source_url": "https://earthquake.usgs.gov/fdsnws/event/1/query?eventid=us7000tbwb&format=geojson", "publisher": "USGS NEIC (ComCat)", "published_date": "2026-08-26", "event_time": "2026-08-26T02:52:10Z", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "Location errors listed as 0 (not a seismic location); derived from imagery per USGS header. ~2.1 km from UNOSAT detachment-zone centroid (derived).", "use": "narrative_only", "notes": "Geodesic distance ComCat point -> UNOSAT DetachmentZone centroid (85.52132E, 28.28913N) = 2.10 km (computed; A_raw/derived_unosat_gdb_measurements.txt).", "verbatim_quote": "The location of this event was estimated from satellite images.", "sweep_ref": "sweep-2026-09-11/A_entries.json[17]" }, { "id": "E-011", "item": "DHM press release: avalanche source coordinates", "value": "snow avalanche near border at N 28°16'50\", E 85°32'15.45\"", "unit": null, "source_url": "https://hydrology.gov.np/cm/files/report_bhotekoshi_1787808964794.pdf", "publisher": "Flood Forecasting Division, Centre for Hydrology and Water Resources Research (CHWRR, formerly DHM), Govt of Nepal", "published_date": "2026-08-27", "event_time": null, "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Low-Medium", "reported_precision_or_uncertainty": "coordinates from preliminary imagery analysis by 'various national and international organisations'", "use": "narrative_only", "notes": "= 28.2806N, 85.5376E (agent conversion). Not a blockage location. Compare USGS popup location 28.271N 85.515E.", "verbatim_quote": "सिमा क्षेत्र नजिक (N 28° 16’ 50’’, E 85° 32’ 15.45’’) हिमपहिरो (Snow Avalanche) गई सो बाट अति उच्च आकस्मिक बहाव आएको देखिन्छ।", "sweep_ref": "sweep-2026-09-11/B_entries.json[37]" }, { "id": "E-012", "item": "DHM press release: M2.6 and M4.4 earthquakes near Rasuwagadhi (source DMG)", "value": "M2.6 at 08:20; M4.4 at 08:37 NPT (Richter), near Rasuwagadhi border area", "unit": null, "source_url": "https://hydrology.gov.np/cm/files/report_bhotekoshi_1787808964794.pdf", "publisher": "Flood Forecasting Division, Centre for Hydrology and Water Resources Research (CHWRR, formerly DHM), Govt of Nepal", "published_date": "2026-08-27", "event_time": "2026-08-26T08:37:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "minute; magnitudes as relayed from Dept. of Mines and Geology", "use": "narrative_only", "notes": "DHM relays Dept. of Mines and Geology local magnitudes (M2.6 at 08:20, M4.4 at 08:37). The 08:20 signal is single-sourced; no causal attribution is made.", "verbatim_quote": "खानी तथा भूगर्भ विभागबाट प्राप्त सुचना अनुसार विहान ८:२० बजे रसुवागढी सिमा क्षेत्र आसपास २.६ रेक्टर स्केलको साथै विहान ८:३७ बजे सोही स्थान आसपास ४.४ रेक्टर स्केलको भूकम्प मापन भएको थियो।", "sweep_ref": "sweep-2026-09-11/B_entries.json[36]" }, { "id": "E-013", "item": "ICIMOD: anomalous seismic signals at Jilong and Zhangmu", "value": "anomalous signals at Jilong seismometer (~12 km from affected area) and unusual activity at Zhangmu", "unit": null, "source_url": "https://www.icimod.org/press-release/major-flash-flood-sweeps-through-nepals-rasuwa-district-raising-fears-of-further-downstream-flooding/", "publisher": "ICIMOD", "published_date": "2026-08-26", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Qualitative", "reported_precision_or_uncertainty": "no times, amplitudes or station codes given", "use": "narrative_only", "notes": "Followed by: 'At present, no causal link has been established between seismic activity and the flood.' Present in first archived version (26 Aug).", "verbatim_quote": "Data from a seismometer in Jilong, approximately 12 kilometres from the affected area showed anomalous signals, while a second station in Zhangmu also recorded unusual activity.", "sweep_ref": "sweep-2026-09-11/B_entries.json[7]" }, { "id": "E-014", "item": "ICIMOD: flood onset and stage rise (reported)", "value": "Bhote Koshi rise began ~09:00 NPT; Trishuli at Galchhi rose up to 9 m within 30 min; Malekhu 7 m over similar period", "unit": null, "source_url": "https://www.icimod.org/press-release/major-flash-flood-sweeps-through-nepals-rasuwa-district-raising-fears-of-further-downstream-flooding/", "publisher": "ICIMOD", "published_date": "2026-08-26", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Low-Medium", "reported_precision_or_uncertainty": "\"reportedly\", \"as much as\"; based on local reports/DHM; verify with DHM station data.", "use": "narrative_only", "notes": "Reported onset from local reports (~09:00 NPT), not a gauge observation. Distinct from the gauge rise onsets E-020/E-021.", "verbatim_quote": "Water levels on the Trishuli River at Galchchi reportedly rose by as much as nine metres within 30 minutes, while levels at Malekhu increased by seven metres over a similar period.", "sweep_ref": "sweep-2026-09-11/A_entries.json[47]" }, { "id": "E-015", "item": "NDRRMA SitRep #01: avalanche location, detached area, lake formation after the event", "value": 20, "unit": "km upstream of Rasuwagadhi; ~1 km2 detached section", "source_url": "https://ndrrma.gov.np/mediafiles/rasuwa/Rasuwa_Flood_SitRep_Temp_ENG_01_01092026.pdf", "publisher": "NDRRMA Situation Report #01", "published_date": "2026-09-01", "event_time": "2026-08-26T08:40:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "'approximately'; 'estimated'", "use": "narrative_only", "notes": "Also: 'approximately 20 km upstream of Rasuwagadhi'; 'an estimated 1 km2 section of rock-glacier material detached' (area, not volume); seismic signal 'generated by the large mass movement itself and was not the triggering cause'. Primary Nepali government source placing lake formation AFTER the main flood. Raw: C_raw/ndrrma_sitrep01_eng.pdf", "verbatim_quote": "Following the avalanche and debris-flood process, multiple temporary lakes formed along the downstream flow path due to channel blockage and sediment deposition.", "sweep_ref": "sweep-2026-09-11/C_entries.json[43]" }, { "id": "E-016", "item": "Collapse time and runout to Gyirong Port (CAS IMHE via Xizang press conference)", "value": "collapse ~10:52 BJT (08:37 NPT) at ~5,200 m; ~22 km to Gyirong Port in about 6-7 min", "unit": null, "source_url": "https://news.cgtn.com/news/2026-08-30/Rescuers-race-against-time-for-survivors-cause-of-mudslide-identified-1Q1EhFbDxxC/p.html", "publisher": "CGTN (Xizang news conference; CAS Institute of Mountain Hazards and Environment)", "published_date": "2026-08-30", "event_time": "2026-08-26T10:52:00+08:00", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "'around'", "use": "narrative_only", "notes": "'the entire process, from the ice-rock avalanche to its impact on Gyirong Port, took only about six to seven minutes.' Note CGTN says 'southern slope of Lantang Lirung'; Xinhua 5 Sep Chinese says 北坡 (north slope). Raw: C_raw/cgtn_0830_cause.html", "verbatim_quote": "Around 10:52 a.m. on August 26, a glacier at an altitude of about 5,200 meters collapsed, sending ice and rock rapidly down the mountainside. The resulting massive mudslide traveled about 22 kilometers before reaching Gyirong Port at an altitude of around 1,800 meters", "sweep_ref": "sweep-2026-09-11/C_entries.json[53]" }, { "id": "E-017", "item": "Guo Zhaocheng: signal start 10:52, Gyirong video impact 10:59; source ~5,140 m", "value": 7, "unit": "minutes", "source_url": "https://dzrb.dzng.com/general/0/NEWS3634819CQMOKPDTKWSZQ", "publisher": "CCTV/Xinhua via Dazhong Daily live blog (expert Guo Zhaocheng; affiliation not captured in retrieved text)", "published_date": "2026-08-27", "event_time": "2026-08-26T10:52:00+08:00", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Medium", "reported_precision_or_uncertainty": "'左右' (about) for elevation", "use": "narrative_only", "notes": "Beijing time. published_date approximate (item undated in live blog; context 27-28 Aug).", "verbatim_quote": "根据信号分析，崩塌开始的时间是10时52分，泥石流冲击到吉隆口岸视频记录的时间是10时59分。", "sweep_ref": "sweep-2026-09-11/C_entries.json[54]" }, { "id": "E-018", "item": "ADRC overview: temporary dam breach time", "value": "temporary dam breach 08:30-08:37 NPT, 26 Aug", "unit": null, "source_url": "https://www.adrc.asia/publications/disaster_report/pdf/2026/ADRC_FL_NPL_Rasuwa_20260826_EN.pdf", "publisher": "Asian Disaster Reduction Center (sourcing IRDR rapid analysis, 28 Aug)", "published_date": "2026-09-08", "event_time": "2026-08-26T08:30:00+05:45", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Low-Medium", "reported_precision_or_uncertainty": "time window 08:30-08:37; 'about'", "use": "narrative_only", "notes": "ADRC chronology sourced to the IRDR Rapid Analysis Report (28 Aug), which was not retrievable (ReliefWeb 403). Conflicts with E-002, E-015, E-016. Recorded without reconciliation.", "verbatim_quote": "At about 08:30-08:37 NPT on 26 August 2026 a temporary natural dam on the Bhote Koshi, formed the previous afternoon by an ice, rock and soil mass failure around Deding in the Langtang region, breached and released a debris-laden flood", "sweep_ref": "sweep-2026-09-11/C_entries.json[49]" }, { "id": "E-019", "item": "ADRC/IRDR: mass failure and dam formation 25 Aug", "value": "mass failure and dam formation 25 Aug 13:00-14:00 NPT; impoundment ~18-19 h (IRDR via ADRC)", "unit": null, "source_url": "https://www.adrc.asia/publications/disaster_report/pdf/2026/ADRC_FL_NPL_Rasuwa_20260826_EN.pdf", "publisher": "ADRC (citing IRDR 28 Aug)", "published_date": "2026-09-08", "event_time": "2026-08-25T13:00:00+05:45", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Low", "reported_precision_or_uncertainty": "time windows as stated", "use": "narrative_only", "notes": "IRDR account relayed by ADRC; IRDR report not retrieved. Conflicts with the CAS-IMHE / Xizang press-conference timing (collapse 10:52 BJT = 08:37 NPT on 26 Aug, ~7 min to Gyirong Port), USGS and NDRRMA (the M5.2 signal is the mass movement itself), CLaSH (7 min leaves no time for a significant lake) and Xu Qiang (no barrier lake in the original process). Recorded without reconciliation.", "verbatim_quote": "The mass blocks the Bhote Koshi and forms a temporary natural dam. Water accumulates behind it for about 18-19 hours.", "sweep_ref": "sweep-2026-09-11/C_entries.json[50]" }, { "id": "E-020", "item": "Galchi (Trishuli at Galchi) gauge rise onset", "value": "last pre-rise 360.623 m @10:20 NPT; first risen 363.583 m @10:30 NPT", "unit": "m (station datum; values ~361 suggest elevation-referenced)", "source_url": "https://dhm.gov.np/hydrology/hms-Single/5705", "publisher": "DHM / CHWRR (telemetry)", "published_date": null, "event_time": "2026-08-26T10:30:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "onset bracketed 10:20-10:30 NPT (+/-10 min); level mm-resolution, provisional", "use": "timing_diagnostic", "notes": "Series retrieved from POST https://dhm.gov.np/site/getRiverWatchBySeriesId_Single (seriesid 36628, date=2026-08-26, UTC day); the link is the station page. Rise onset bracketed by the last flat and first risen 10-min samples; provisional real-time telemetry. Galchhi and Malekhu sample the same propagating wave.", "observation_dependence": "same_event_correlated", "verbatim_quote": null, "sweep_ref": "sweep-2026-09-11/B_entries.json[39]" }, { "id": "E-021", "item": "Malekhu (Trishuli at Furke Khola) gauge rise onset", "value": "last pre-rise 3.351 m @11:10 NPT; 3.963 m @11:20; 7.781 m @11:30; 10.482 m @11:40 (last value)", "unit": "m", "source_url": "https://dhm.gov.np/hydrology/hms-Single/5611", "publisher": "DHM / CHWRR (telemetry)", "published_date": null, "event_time": "2026-08-26T11:20:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "onset bracketed 11:10-11:20 NPT (+/-10 min); level to mm, provisional", "use": "timing_diagnostic", "notes": "Series retrieved from POST https://dhm.gov.np/site/getRiverWatchBySeriesId_Single (seriesid 31967, date=2026-08-26, UTC day); the link is the station page. Rise onset bracket 11:10-11:20 NPT. Station destroyed after the 11:40 sample: the recorded rise (+7.13 m) is a lower bound (censored).", "observation_dependence": "same_event_correlated", "verbatim_quote": null, "sweep_ref": "sweep-2026-09-11/B_entries.json[41]" }, { "id": "E-022", "item": "Galchi gauge peak and rise duration", "value": "peak 369.451 m @10:50 NPT; rise +8.83 m from 10:20 to 10:50 (30 min); 11:00 369.381; back to 363.0 by 12:50", "unit": "m", "source_url": "https://dhm.gov.np/hydrology/hms-Single/5705", "publisher": "DHM / CHWRR (telemetry)", "published_date": null, "event_time": "2026-08-26T10:50:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "peak time +/-10 min (true peak may fall between samples)", "use": "stage_observational_check", "notes": "Rise DURATION (not lag). Galchi warning level in metadata = 367 (no danger level); 367 m first exceeded at 10:40 sample (368.170) and last at 11:40 (367.089). Metadata is as of 11 Sep 2026; not confirmed that this threshold was configured on 26 Aug. Raw 10-min instantaneous water level (WL_I_10M) from DHM telemetry, retrieved via dhm.gov.np endpoint; JSON timestamps are UTC (+00:00) and were converted to NPT (+05:45); DHM table view shows the same values in 12-h NPT. Provisional, unvalidated real-time data. The endpoint serves only ~16 days back (no data before 2026-08-26T00:00Z on 11 Sep) - archived copies in B_raw.", "observation_dependence": "same_event_correlated", "verbatim_quote": null, "sweep_ref": "sweep-2026-09-11/B_entries.json[40]" }, { "id": "E-023", "item": "ICIMOD: Galchhi water-level rise (magnitude and duration)", "value": "~9 (\"as much as nine metres\") within 30 minutes", "unit": "m", "source_url": "https://www.icimod.org/press-release/major-flash-flood-sweeps-through-nepals-rasuwa-district-raising-fears-of-further-downstream-flooding/", "publisher": "ICIMOD", "published_date": "2026-08-26", "event_time": "2026-08-26T10:20:00+05:45/2026-08-26T10:50:00+05:45", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "'as much as'; 'reportedly'; no timestamps given", "use": "corroboration", "notes": "'Within 30 minutes' is the DURATION of the rise at the gauge, not a lag or arrival time. Confirmed by DHM telemetry E-022. Source of the 6-12 m check band.", "observation_dependence": "same_event_correlated", "verbatim_quote": "Water levels on the Trishuli River at Galchchi reportedly rose by as much as nine metres within 30 minutes, while levels at Malekhu increased by seven metres over a similar period.", "sweep_ref": "sweep-2026-09-11/B_entries.json[1]" }, { "id": "E-024", "item": "ICIMOD: Malekhu water-level rise (magnitude and duration)", "value": "~7 over 'a similar period' (~30 min)", "unit": "m", "source_url": "https://www.icimod.org/press-release/major-flash-flood-sweeps-through-nepals-rasuwa-district-raising-fears-of-further-downstream-flooding/", "publisher": "ICIMOD", "published_date": "2026-08-26", "event_time": "2026-08-26T11:10:00+05:45/2026-08-26T11:40:00+05:45", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "'reportedly'; 'similar period' unquantified", "use": "corroboration", "notes": "Duration of rise, not arrival lag. DHM telemetry E-021 shows the value is censored.", "observation_dependence": "same_event_correlated", "verbatim_quote": "levels at Malekhu increased by seven metres over a similar period.", "sweep_ref": "sweep-2026-09-11/B_entries.json[2]" }, { "id": "E-025", "item": "Derived: gauge rise-onset differences along corridor (not travel speeds)", "value": "Galchi->Malekhu ~50 min (+/-10); Malekhu->Kali Khola ~2 h (+/-10 min); Kali Khola->Devghat ~1 h (+/-20 min)", "unit": "min", "source_url": "https://dhm.gov.np/hydrology/hms-Single/5705", "publisher": "GOATAI derivation from DHM 10-min telemetry", "published_date": null, "event_time": "2026-08-26T10:20:00+05:45/2026-08-26T11:20:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "each onset bracketed by one 10-min interval, so differences carry +/-10 min (Devghat +/-20)", "use": "timing_diagnostic", "notes": "Galchhi -> Malekhu onset difference (~50 min, bracket 40-60 min). Derived from E-020 and E-021, so not independent of the two arrival checks.", "observation_dependence": "partially_dependent", "verbatim_quote": null, "sweep_ref": "sweep-2026-09-11/B_entries.json[47]" }, { "id": "E-026", "item": "Rasuwagadi (Bhotekoshi at Rasuwagadi) last telemetry", "value": "1.620 m @08:40 NPT (02:55Z); 18 values 05:50-08:40, slowly falling from 1.776 m; nothing after", "unit": "m", "source_url": "https://dhm.gov.np/site/getRiverWatchBySeriesId_Single (POST seriesid=23251, date=2026-08-26, period=1; station page https://dhm.gov.np/hydrology/hms-Single/4913)", "publisher": "DHM / CHWRR (telemetry)", "published_date": null, "event_time": "2026-08-26T08:40:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "0.001 m; loss between 08:40 and 08:50 if cadence 10 min", "use": "narrative_only", "notes": "No flood signal recorded. Station 4913 (28.271297N 85.377649E), metadata WL 6.0 m, DL 7 m. Stopped transmitting is not proof of destruction time, but DHM press release states it was swept away before next transmission. Raw 10-min instantaneous water level (WL_I_10M) from DHM telemetry, retrieved via dhm.gov.np endpoint; JSON timestamps are UTC (+00:00) and were converted to NPT (+05:45); DHM table view shows the same values in 12-h NPT. Provisional, unvalidated real-time data. The endpoint serves only ~16 days back (no data before 2026-08-26T00:00Z on 11 Sep) - archived copies in B_raw.", "verbatim_quote": null, "sweep_ref": "sweep-2026-09-11/B_entries.json[42]" }, { "id": "E-027", "item": "Syabrubesi (Bhote Koshi at Shyaprubesi) last telemetry", "value": "3.804 m @08:50 NPT (03:05Z); no rise; nothing after", "unit": "m", "source_url": "https://dhm.gov.np/site/getRiverWatchBySeriesId_Single (POST seriesid=2810, date=2026-08-26, period=1; station page https://dhm.gov.np/hydrology/hms-Single/191)", "publisher": "DHM / CHWRR (telemetry)", "published_date": null, "event_time": "2026-08-26T08:50:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "0.001 m", "use": "narrative_only", "notes": "Langtang Khola at Syabrubesi (series 2788) also stops after 08:50 (2.809 m). Metadata WL 5.50 m, no DL. Raw 10-min instantaneous water level (WL_I_10M) from DHM telemetry, retrieved via dhm.gov.np endpoint; JSON timestamps are UTC (+00:00) and were converted to NPT (+05:45); DHM table view shows the same values in 12-h NPT. Provisional, unvalidated real-time data. The endpoint serves only ~16 days back (no data before 2026-08-26T00:00Z on 11 Sep) - archived copies in B_raw.", "verbatim_quote": null, "sweep_ref": "sweep-2026-09-11/B_entries.json[43]" }, { "id": "E-028", "item": "Betrawati (Trishuli at Betrawati) last telemetry", "value": "3.549 m @09:20 NPT (03:35Z); flat 3.52-3.56 m since 08:30; nothing after", "unit": "m", "source_url": "https://dhm.gov.np/site/getRiverWatchBySeriesId_Single (POST seriesid=943, date=2026-08-26, period=1; station page https://dhm.gov.np/hydrology/hms-Single/52)", "publisher": "DHM / CHWRR (telemetry)", "published_date": null, "event_time": "2026-08-26T09:20:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "0.001 m", "use": "narrative_only", "notes": "No rise recorded before loss despite DHM receiving flood information at 09:00-09:05. Metadata WL 4.1, DL 5.0. Raw 10-min instantaneous water level (WL_I_10M) from DHM telemetry, retrieved via dhm.gov.np endpoint; JSON timestamps are UTC (+00:00) and were converted to NPT (+05:45); DHM table view shows the same values in 12-h NPT. Provisional, unvalidated real-time data. The endpoint serves only ~16 days back (no data before 2026-08-26T00:00Z on 11 Sep) - archived copies in B_raw.", "verbatim_quote": null, "sweep_ref": "sweep-2026-09-11/B_entries.json[44]" }, { "id": "E-029", "item": "DHM press release: Furke (Malekhu) threshold crossings and max", "value": "warning (7 m) at 11:20; danger (8 m) at 11:40; max 10.48 m, then station swept away", "unit": "m", "source_url": "https://hydrology.gov.np/cm/files/report_bhotekoshi_1787808964794.pdf", "publisher": "Flood Forecasting Division, Centre for Hydrology and Water Resources Research (CHWRR, formerly DHM), Govt of Nepal", "published_date": "2026-08-27", "event_time": "2026-08-26T11:40:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "times on 10-min grid; 0.01 m", "use": "narrative_only", "notes": "Telemetry: 11:20 = 3.963 m (below 7 m), 11:30 = 7.781 m, 11:40 = 10.482 m. So the 7 m crossing lies between 11:20 and 11:30 samples; DHM's '11:20' appears to denote the start of that interval (or the rise onset). 10.48 is the last transmitted value, not a true peak.", "verbatim_quote": "जलमापन तथ्याङ्क अनुसार फुर्के (मलेखु) जलमापन केन्द्रमा विहान ११:२० बजे जलसतह सतर्कता तह (७ मि.) र ११:४० बजे खतरा तह (८ मि.) पार गर्दै उच्चतम १०.४८ मि. पुगि केन्द्र बगाएको थियो।", "sweep_ref": "sweep-2026-09-11/B_entries.json[34]" }, { "id": "E-030", "item": "DHM report: Phurke (Malekhu) warning-level crossing", "value": "11:26 NPT", "unit": null, "source_url": "https://hydrology.gov.np/cm/files/Bhotekoshi-Trishuli-Narayani_Flood_Report_CHWRR_1%20_1787809133090.pdf", "publisher": "Flood Forecasting Division, Centre for Hydrology and Water Resources Research (CHWRR, formerly DHM), Govt of Nepal", "published_date": "2026-08-26", "event_time": "2026-08-26T11:26:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "minute stated but not a sample time (10-min telemetry at :x0); likely message/log time", "use": "narrative_only", "notes": "DHM technical report gives 11:26 (warning) / 11:43 (danger); the 27 Aug press release gives 11:20 / 11:40 (E-029). Probably message/log times; telemetry shows 7 m first exceeded at the 11:30 sample.", "verbatim_quote": "११:२६ बजेः फुर्के (मलेखु) जलमापन केन्द्रमा जलसतहले सतर्कता तह पार गरी बढ्दो क्रममा रहेको।", "sweep_ref": "sweep-2026-09-11/B_entries.json[18]" }, { "id": "E-031", "item": "DHM report: Devghat peak stage", "value": "6.57 m at 16:00 NPT, then falling", "unit": "m", "source_url": "https://hydrology.gov.np/cm/files/Bhotekoshi-Trishuli-Narayani_Flood_Report_CHWRR_1%20_1787809133090.pdf", "publisher": "Flood Forecasting Division, Centre for Hydrology and Water Resources Research (CHWRR, formerly DHM), Govt of Nepal", "published_date": "2026-08-26", "event_time": "2026-08-26T16:00:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "0.01 m; 10-min sampling", "use": "narrative_only", "notes": "Telemetry (series 4140): 6.573 m @16:00, 6.572 m @16:10. Devghat thresholds (station metadata): warning 7.3 m, danger 9 m -> peak stayed below warning. Report at 13:20 had predicted ~3 m rise to ~8 m.", "verbatim_quote": "१६:०० बजेः देवघाट जलमापन केन्द्रमा जलसतह उच्चतम विन्दु ६.५७ मिटर पुगेको र तत् पश्चात घट्न शुरु भएको।", "sweep_ref": "sweep-2026-09-11/B_entries.json[23]" }, { "id": "E-032", "item": "DHM report: Devghat flood volumes (total and excess over base flow)", "value": "total ~57.40 Mm3; excess ~19.96 Mm3; base flow 2,600 m3/s; window 14:10-18:00 NPT", "unit": "million m3", "source_url": "https://hydrology.gov.np/cm/files/Bhotekoshi-Trishuli-Narayani_Flood_Report_CHWRR_1%20_1787809133090.pdf", "publisher": "Flood Forecasting Division, Centre for Hydrology and Water Resources Research (CHWRR, formerly DHM), Govt of Nepal", "published_date": "2026-08-26", "event_time": null, "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "preliminary; 24 x 10-min rectangles; base flow assumed constant", "use": "narrative_only", "notes": "Rating-curve volume at Devghat, 168 km below the border and beyond the modelled corridor. A clear-water rating applied to a sediment-laden flood; includes entrained and tributary water. Not comparable to any single store without a conversion model.", "verbatim_quote": "यस अवधिमा २,६०० m³/s लाई आधार बहाव (base flow) का रूपमा लिँदा देवघाटबाट पार भएको कुल पानीको अनुमानित आयतन करिब ५७.४० मिलियन घनमिटर रहेको", "sweep_ref": "sweep-2026-09-11/B_entries.json[25]" }, { "id": "E-033", "item": "DHM: information of flood entry received by Flood Forecasting Division", "value": "09:05 NPT (sec.1); timeline row 09:00 (DAO Rasuwa + Betrawati station staff); warnings from 09:15", "unit": null, "source_url": "https://hydrology.gov.np/cm/files/Bhotekoshi-Trishuli-Narayani_Flood_Report_CHWRR_1%20_1787809133090.pdf", "publisher": "Flood Forecasting Division, Centre for Hydrology and Water Resources Research (CHWRR, formerly DHM), Govt of Nepal", "published_date": "2026-08-26", "event_time": "2026-08-26T09:05:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "minute stated; internal 09:00 vs 09:05 difference", "use": "narrative_only", "notes": "Timeline row: '९:०० बजेः ... सूचना जिल्ला प्रसासन कार्यालय, रसुवाबाट र बेत्रावतीमा रहेका जलमापनकेन्द्रको कर्मचारी मार्फत महाशाखालाइ प्राप्त भएको'. This is a notification time, not a gauge observation.", "verbatim_quote": "मिति २०८३ भदौ १० गते बिहान ०९:०५ बजे यस महाशाखालाइ रसुवा जिल्ला स्थित भोटेकोशी नदीमा तिब्बततर्फबाट ठूलो बाढी प्रवेश गरेको सूचना प्राप्त भएको थियो।", "sweep_ref": "sweep-2026-09-11/B_entries.json[14]" }, { "id": "E-034", "item": "Pre-event stage trend, 05:50 NPT to flood onset", "value": "falling at Rasuwagadhi (1.776 -> 1.620 m by 08:40), Galchhi (361.97 -> 360.62 m by 10:20) and Malekhu (4.32 -> 3.35 m by 11:10)", "unit": "m", "source_url": "https://dhm.gov.np/hydrology/hms-Single/5705", "publisher": "DHM Nepal (10-min telemetry, provisional)", "published_date": null, "event_time": "2026-08-26T05:50:00+05:45/2026-08-26T11:10:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "provisional real-time data; 10-min samples", "use": "narrative_only", "notes": "Derived by GOATAI from the archived series (sim-claude cases/nepal_2026/inputs/dhm_telemetry_20260826_provisional.csv). Non-diagnostic: the preceding days' series are no longer on the public endpoint, and hydropower operations are not accounted for.", "sweep_ref": null }, { "id": "E-035", "item": "Galchhi stage duration above pre-flood level", "value": "more than 1 m above the 10:20 pre-rise level (360.623 m) from the 10:30 sample through the 13:30 sample; below it by 13:40", "unit": "h (about 3)", "source_url": "https://dhm.gov.np/hydrology/hms-Single/5705", "publisher": "DHM Nepal (10-min telemetry, provisional)", "published_date": null, "event_time": "2026-08-26T10:30:00+05:45/2026-08-26T13:40:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "10-min samples; +/-10 min on each end; stage only, no rating curve", "use": "narrative_only", "notes": "Derived by GOATAI from the archived series (sim-claude cases/nepal_2026/inputs/dhm_telemetry_20260826_provisional.csv). Bears on the hydrograph-duration assumption of the Manning inversion; not a volume.", "sweep_ref": null }, { "id": "E-036", "item": "Devghat (Narayani) gauge rise onset", "value": "last flat 4.639 m @14:10 NPT; rising from 14:20 (4.656 m), clear by 14:40 (4.800 m)", "unit": "m", "source_url": "https://dhm.gov.np/hydrology/hms-Single/265", "publisher": "DHM Nepal (10-min telemetry, provisional)", "published_date": null, "event_time": "2026-08-26T14:20:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "provisional real-time data; onset bracketed by one 10-min interval", "use": "narrative_only", "notes": "Read from the archived series (sim-claude cases/nepal_2026/inputs/dhm_telemetry_20260826_provisional.csv), the same source as E-020/E-021. Devghat is 168 km below the border and outside the modelled corridor, so it is not a model check. Peak stage is E-031. Consistent with the reach offsets in E-025.", "sweep_ref": null }, { "id": "E-037", "item": "Derived: detection-chain intervals from T0", "value": "T0 to institutional awareness 23-28 min (09:00-09:05 NPT); T0 to first warnings issued 38 min (09:15 NPT)", "unit": "min", "source_url": "https://hydrology.gov.np/cm/files/Bhotekoshi-Trishuli-Narayani_Flood_Report_CHWRR_1%20_1787809133090.pdf", "publisher": "GOATAI derivation from E-002 and E-033", "published_date": null, "event_time": "2026-08-26T08:37:10+05:45/2026-08-26T09:15:00+05:45", "accessed_date": "2026-09-13", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "arithmetic on the stated clock times; DHM gives both 09:00 and 09:05 for notification, so awareness is a window, and 09:15 is the stated start of warnings, not a per-message timestamp", "use": "narrative_only", "notes": "Parents: E-002 (T0 = 08:37:10 NPT) and E-033 (notification 09:00/09:05; warnings from 09:15). Reconstructed after the fact from what this event's chain happened to produce. Not a system performance measure and not a forecast.", "sweep_ref": null }, { "id": "E-038", "item": "Derived: lead time between first warning issued and local gauge rise onset", "value": "Galchhi 65-75 min; Malekhu 115-125 min; Devghat about 295-305 min (E-025 reach offsets give a consistent 265-335 min window)", "unit": "min", "source_url": "https://dhm.gov.np/hydrology/hms-Single/5705", "publisher": "GOATAI derivation from E-033, E-020, E-021, E-036, E-025", "published_date": null, "event_time": "2026-08-26T09:15:00+05:45/2026-08-26T14:20:00+05:45", "accessed_date": "2026-09-13", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "each onset is bracketed by one 10-min sample, so every lead time carries +/-10 min; the warning time is a stated start, not a per-recipient delivery time", "use": "narrative_only", "notes": "Parents: E-033 (warnings from 09:15), E-020 (Galchhi onset 10:20-10:30), E-021 (Malekhu 11:10-11:20), E-036 (Devghat 14:10-14:20), E-025 (reach offsets), E-002 (T0). These are the lead times this event's detection chain produced, reconstructed afterwards. They are not a system performance claim and not a forecast of what any warning system would achieve. No lead time existed above Betrawati: E-026, E-027 and E-028 stop before any rise.", "sweep_ref": null }, { "id": "E-039", "item": "Derived: telemetry-loss sequence along the corridor", "value": "Rasuwagadhi last transmission 08:40 (T+3 min), Syabrubesi 08:50 (T+13 min), Betrawati 09:20 (T+43 min); strictly downstream order; none recorded a rise. Apparent mean celerity over the 45.8 km between the first and last loss, on model chainage, 19 m/s (24.6 m/s Rasuwagadhi to Syabrubesi, 17.2 m/s Syabrubesi to Betrawati)", "unit": "min; m/s", "source_url": "https://dhm.gov.np/hydrology/hms-Single/4913", "publisher": "GOATAI derivation from E-026, E-027, E-028 and the corridor chainage of sim-claude edff56c", "published_date": null, "event_time": "2026-08-26T08:40:00+05:45/2026-08-26T09:20:00+05:45", "accessed_date": "2026-09-13", "source_tier": "primary", "confidence": "Low-Medium", "reported_precision_or_uncertainty": "each last-transmission time is an UPPER BOUND on the time of loss, resolved only to the 10-minute polling interval (-10/+0 min); the celerity additionally rests on OSM/SRTM model chainage, not surveyed distances, so it is order-of-magnitude only", "use": "narrative_only", "notes": "Parents: E-026, E-027, E-028 (last transmissions), E-002 (T0), plus station chainages from the corridor model (sim-claude edff56c). Loss of transmission has causes other than destruction — power, communications, the station itself — so the ordering is CONSISTENT WITH the wave passing each site, not proof of it. DHM separately states the Rasuwagadhi station was swept away (E-026). The second loss (08:50) precedes the first warning (09:15) by 25 min; the third (09:20) follows it by 5 min. A design finding recovered from the record afterwards, never a method that was available on the day.", "sweep_ref": null }, { "id": "E-040", "item": "DHM: debris blocked river ~20 km upstream of Miteri Bridge (Chinese imagery)", "value": 20, "unit": "km upstream of Miteri Bridge", "source_url": "https://kathmandupost.com/national/2026/08/26/ice-avalanche-debris-lake-may-have-triggered-bhotekoshi-flood", "publisher": "The Kathmandu Post (DHM FFD chief Binod Parajuli)", "published_date": "2026-08-26", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Low-Medium", "reported_precision_or_uncertainty": "'about'; preliminary satellite imagery", "use": "scenario_bound", "notes": "DHM official (B. Parajuli) via Kathmandu Post, based on Chinese imagery. The present simulation places the suspected blockage at this ~20 km figure (chainage 7.5 km).", "verbatim_quote": "Binod Parajuli, chief of the department's Flood Forecasting Division, said preliminary satellite imagery received from Chinese authorities showed that debris had blocked the river about 20 kilometres upstream of the Miteri Bridge, forming a temporary lake that subsequently burst.", "sweep_ref": "sweep-2026-09-11/C_entries.json[41]" }, { "id": "E-041", "item": "DHM: Lende Khola blockage ~10 km upstream of Miteri Bridge, Tibetan side", "value": 10, "unit": "km upstream of Miteri Bridge", "source_url": "https://en.himalpress.com/bhotekoshi-flood-risk-persists-as-lende-khola-is-still-blocked-officials/", "publisher": "HimalPress English (DHM Flood Forecasting Division, Binod Parajuli)", "published_date": "2026-08-26", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Low-Medium", "reported_precision_or_uncertainty": "'about'; 'believed to have been'", "use": "narrative_only", "notes": "Same DHM official, same day, 6.5 h after the flood, referring to a lake 'not yet fully drained'. Probably a different feature from E-040 (inference); not reconciled.", "verbatim_quote": "According to the Flood Forecasting Division under the Department of Hydrology and Meteorology, the Lende Khola is believed to have been blocked about 10 kilometers upstream from the Miteri Bridge on the Tibetan side.", "sweep_ref": "sweep-2026-09-11/C_entries.json[39]" }, { "id": "E-042", "item": "NDRRMA: snow-rock landslide ~20 km NE of Rasuwagadhi (26 Aug)", "value": 20, "unit": "km northeast of Rasuwagadhi border crossing", "source_url": "https://english.onlinekhabar.com/what-caused-the-rasuwa-flood.html", "publisher": "OnlineKhabar English (NDRRMA, citing Planet Labs imagery)", "published_date": "2026-08-26", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Medium", "reported_precision_or_uncertainty": "'around'", "use": "narrative_only", "notes": "Published 2026-08-26 21:09 NPT. Free Press Journal quotes a translated NDRRMA X post with same wording (C_raw/freepress.html). Straight-line Rasuwagadhi to USGS M5.2 location is ~13.5 km; '20 km' is likely along-valley or approximate.", "verbatim_quote": "The National Disaster Risk Reduction and Management Authority (NDRRMA) said a snow-and-rock landslide occurred around 20 kilometres northeast of the Rasuwagadhi border point, citing satellite imagery from Planet Labs.", "sweep_ref": "sweep-2026-09-11/C_entries.json[42]" }, { "id": "E-043", "item": "ICIMOD statement on possible blockage (mechanism-relevant)", "value": "experts assessing whether debris temporarily blocked river at a narrow section forming a landslide dam", "unit": null, "source_url": "https://www.icimod.org/press-release/major-flash-flood-sweeps-through-nepals-rasuwa-district-raising-fears-of-further-downstream-flooding/", "publisher": "ICIMOD", "published_date": "2026-08-26", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Qualitative", "reported_precision_or_uncertainty": "Hypothesis under assessment, not a finding. Page modified 2026-08-28T13:49:20+05:45.", "use": "narrative_only", "notes": "Same release quotes S. Sanyal (ICIMOD): \"most probably triggered by an ice avalanche blocked the river and released a sudden surge downstream. This still needs to be confirmed\". No ICIMOD boundary/extent dataset found in the release. ICIMOD is outside agent A core scope - cross-check with the ICIMOD/DHM agent.", "verbatim_quote": "Experts are also assessing whether debris temporarily blocked the river at a narrow section, forming a landslide dam.", "sweep_ref": "sweep-2026-09-11/A_entries.json[46]" }, { "id": "E-044", "item": "DHM report: blockage/lake status from China", "value": "13:35 NPT: per information from China side, lake at river-blockage site not yet fully drained", "unit": null, "source_url": "https://hydrology.gov.np/cm/files/Bhotekoshi-Trishuli-Narayani_Flood_Report_CHWRR_1%20_1787809133090.pdf", "publisher": "Flood Forecasting Division, Centre for Hydrology and Water Resources Research (CHWRR, formerly DHM), Govt of Nepal", "published_date": "2026-08-26", "event_time": "2026-08-26T13:35:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Qualitative", "reported_precision_or_uncertainty": "no location/distance given", "use": "narrative_only", "notes": "The DHM technical report and press release give NO '~10 km upstream of Miteri Bridge' statement. See KP 26 Aug entry (Parajuli: ~20 km upstream of Miteri Bridge).", "verbatim_quote": "१३:३५ बजेः चीनतर्फबाट प्राप्त सूचनाअनुसार नदी थुनिएको स्थानमा बनेको ताल अझै पूर्णरूपमा नखुलेको जानकारी।", "sweep_ref": "sweep-2026-09-11/B_entries.json[21]" }, { "id": "E-045", "item": "Derived: interval between seismic origin and first warning issued", "value": "37.8 min (08:37:10 NPT origin to 09:15 NPT first warnings)", "unit": "min", "source_url": "https://earthquake.usgs.gov/fdsnws/event/1/query?eventid=us7000tbwb&format=geojson", "publisher": "GOATAI derivation from E-002 and E-033", "published_date": null, "event_time": "2026-08-26T08:37:10+05:45/2026-08-26T09:15:00+05:45", "accessed_date": "2026-09-13", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "origin time is resolved to the second; 09:15 is DHM's stated start of warnings, not a per-recipient delivery time", "use": "narrative_only", "notes": "Parents: E-002 (origin), E-033 (notification 09:00-09:05 by telephone and station staff, warnings from 09:15). NOT a claim that a warning could have been issued minutes after the failure: an automatic seismic solution takes minutes rather than seconds, the event was initially catalogued as an M4.4 EARTHQUAKE (E-012, E-003) and only later reclassified as landslide-type (E-002), and the published classification wording was still being revised on 28 August (E-006 -> E-005). The missing capability is real-time discrimination of landslide-type signals and a route from a seismic detection into the corridor's warning chain; neither existed.", "sweep_ref": null }, { "id": "E-046", "item": "Sentinel-2 L2A scene availability over the corridor, by window", "value": "27 Aug-13 Sep 2026 (post-event): 0 scenes below 40% cloud. 1 Apr-20 Jun 2026 (pre-event): 55. 1 Jun-7 Jul 2025 (pre-2025-event): 8. 9 Jul-30 Sep 2025 (post-2025-event): 16, best 1.0% on 26 Sep 2025", "unit": "scene count", "source_url": "https://earth-search.aws.element84.com/v1", "publisher": "GOATAI census of the Element84 Earth Search STAC catalogue (Sentinel-2 L2A, AWS open data)", "published_date": null, "event_time": "2026-08-27/2026-09-13", "accessed_date": "2026-09-13", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "scene-level cloud cover is whole-scene, so a cloudy scene may still have a clear corridor and vice versa; counts are for the corridor bounding box 84.70-85.60 E, 27.70-28.35 N", "use": "narrative_only", "notes": "Measured by GOATAI on 13 Sep 2026 by querying the public catalogue; no imagery was processed for this entry. It quantifies why the 2026 post-event corridor state cannot yet be measured optically, and why the 2025 analogue can. The 2025 post-event window shows the post-monsoon clearing that the 2026 window has not yet reached.", "sweep_ref": null }, { "id": "E-047", "item": "Sentinel-2 spectral water indices fail over this turbid corridor (negative result)", "value": "At the Galchhi channel centre green 895 vs NIR 2334 (NDWI max -0.074 over a 300 m box, fraction >= 0 is 0.000); MNDWI with SWIR-1.6 gives max 0.017 at Galchhi and -0.082 at Malekhu, and an off-channel hillslope control is indistinguishable at -0.044", "unit": "index value", "source_url": "https://earth-search.aws.element84.com/v1", "publisher": "GOATAI measurement on Sentinel-2 L2A scene S2C_45RTL_20260524_0_L2A (AWS open data)", "published_date": null, "event_time": "2026-05-24", "accessed_date": "2026-09-13", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "10 m green/NIR, 20 m SWIR-1.6 resampled to the 10 m grid; 300-400 m boxes centred on the channel; controls at two perennial reaches and one off-channel hillslope", "use": "narrative_only", "notes": "Measured while attempting the EO change-detection set. Sediment-laden monsoon flow reflects strongly in NIR and SWIR, so neither NDWI nor MNDWI separates this river from bare ground at Sentinel-2 resolution: a 110 m perennial channel and a hillslope return the same class. Consequence: no Sentinel-2 width or wet-extent product can be published for this corridor, and the first width attempt (which returned 0 m at every transect under an NDWI>=0 rule) is discarded rather than reported. Transect-grade width needs Planet or WorldView optical, or calibrated/terrain-corrected SAR. A reusable negative result, not a limitation of this event.", "sweep_ref": null }, { "id": "E-050", "item": "Impact-crater pond storage volume (the '1.4 Mm3' figure) - English origin", "value": 1.4, "unit": "million m3", "source_url": "https://english.news.cn/20260830/219b22b13e3b46d5a6a1f4152f998ed9/c.html", "publisher": "Xinhua (relaying China Ministry of Water Resources)", "published_date": "2026-08-30", "event_time": "2026-08-30T11:23:00+08:00", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "'about'; method of volume estimation not stated", "use": "narrative_only", "notes": "PROVENANCE VERDICT for the '~1.4 Mm3' figure: post-event store; reported estimate (MWR, method unpublished). Impact-crater pond ~5.6 km above the lower barrier lake, measured 30 Aug. No source describes it as the store that produced the 26 Aug main wave. The 4 Sep page treated it as the reported impoundment and centred the medium member on it; that use is withdrawn. The 4 Sep freeze cited Kathmandu Post 27 Aug for it, which cannot be its origin (published before the 30 Aug measurement).", "verbatim_quote": "At 11:23 a.m. Sunday, the crater had a water surface area of about 108,000 square meters, down 19,000 square meters from 7 a.m., with a storage volume of about 1.4 million cubic meters.", "sweep_ref": "sweep-2026-09-11/C_entries.json[0]" }, { "id": "E-051", "item": "Impact-crater pond storage volume, 31 Aug (SAR)", "value": 0.65, "unit": "million m3 (65万立方米)", "source_url": "https://dzrb.dzng.com/general/0/NEWS3634819CQMOKPDTKWSZQ", "publisher": "Dazhong Daily live blog (CCTV News relaying MWR)", "published_date": "2026-08-31", "event_time": "2026-08-31T05:14:00+08:00", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "约 (about); SAR outer-boundary area", "use": "narrative_only", "notes": "Area ~83,000 m2 (30 Aug 19:00 derived ~97,000 m2). Implied mean depth 7.8 m vs 13.0 m on 30 Aug - so MWR volumes are NOT area x fixed 13 m depth; consistent with a bowl-shaped (hypsometric) estimate. published_date approximated to item date; live blog page last updated 2026-09-09. Raw: C_raw/cn_dzrb_mwr_live.html", "verbatim_quote": "根据8月31日5时14分SAR影像分析，尼泊尔错坚河冲击坑水体外边界面积约8.3万平方米，较30日19时减小1.4万平方米，蓄水量约65万立方米。", "sweep_ref": "sweep-2026-09-11/C_entries.json[6]" }, { "id": "E-052", "item": "Implied mean depth of impact-crater pond (derived check of '0.11 km2 x 13 m' hypothesis)", "value": 13.0, "unit": "m", "source_url": "https://tidenews.com.cn/news.html?id=3544355", "publisher": "Arithmetic by this analysis from MWR figures", "published_date": null, "event_time": "2026-08-30T11:23:00+08:00", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "High", "reported_precision_or_uncertainty": "derived: 1.4e6 m3 / 1.08e5 m2 = 12.96 m; 31 Aug: 6.5e5/8.3e4 = 7.8 m", "use": "narrative_only", "notes": "Derived check: 1.4e6 m3 / 108,000 m2 = 13.0 m mean depth. No source states an assumed depth; MWR's 31 Aug pair implies 7.8 m, so no fixed-depth multiplier fits. The '0.11 km2 x 13 m' derivation hypothesis is not supported.", "verbatim_quote": "冲击坑水面面积约10.8万平方米...蓄水量约140万立方米", "sweep_ref": "sweep-2026-09-11/C_entries.json[10]" }, { "id": "E-053", "item": "Funnel-shaped water body beneath ice-avalanche source area (upper blockage >120,000 m2)", "value": 120000, "unit": "m2 (lower bound); depth unknown", "source_url": "https://news.qq.com/rain/a/20260829A01CMH00", "publisher": "CCTV News 'News 1+1' (MNR Geological Hazard Technical Guidance Center, Chen Hongqi)", "published_date": "2026-08-29", "event_time": "2026-08-28", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "'exceeds' (超过); depth explicitly unknown", "use": "narrative_only", "notes": "Earliest Chinese official quantification of the upper pond found. Programme is 'day three' of rescue (26 Aug = day 1), i.e. aired 28 Aug; posted 29 Aug 01:47. Depth unknown on this date - so any volume at this stage would have required an assumed depth. Raw: C_raw/cn_qq_0829.html", "verbatim_quote": "除了堰塞湖之外，在冰崩源区的底部，实际上还有一个斗状的水体——我们测算它的面积超过12万平方米，但水深目前还不清楚。", "sweep_ref": "sweep-2026-09-11/C_entries.json[8]" }, { "id": "E-054", "item": "UNOSAT 4260 barrier lake 1 (near Nepal-China border) area", "value": "approximately 12 (map inset label 11.92 ha; 990 m x 253 m)", "unit": "ha", "source_url": "https://unosat.org/products/4260", "publisher": "UNOSAT (UNITAR)", "published_date": "2026-08-31", "event_time": "2026-08-28", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "\"approximately 12 ha\"; inset label 11.92 ha (read from map JPG); GDB polygon geodesic area 119,182 m2 (computed).", "use": "narrative_only", "notes": "Cartosat-3 (1.1 m), 28 Aug 2026. Lake polygon centroid 85.48226E, 28.33281N. NOTE: a \">120,000 m2\" figure is NOT supported for this lake - mapped area is 119,182 m2 (just under 120,000). Lake is located on the border river (Chusumdo Tsangpo/Lende Khola) per map.", "verbatim_quote": "The first barrier lake, with an estimated area of approximately 12 ha, is located near the Nepal–China border, approximately 11 km east of the Rasuwagadhi Friendship Bridge, measured along the Chusumdo Tsangpo River and following the approximate mudflow/rockflow path.", "sweep_ref": "sweep-2026-09-11/A_entries.json[25]" }, { "id": "E-055", "item": "UNOSAT 4260 barrier lake 2 (near source) area", "value": "approximately 19 (map inset label 19.51 ha; 625 m x 413 m)", "unit": "ha", "source_url": "https://unosat.org/products/4260", "publisher": "UNOSAT (UNITAR)", "published_date": "2026-08-31", "event_time": "2026-08-28", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "\"approximately 19 ha\"; inset label 19.51 ha; GDB polygon geodesic area 195,124 m2 (computed).", "use": "narrative_only", "notes": "Polygon centroid 85.51074E, 28.29291N; 1.1 km from detachment-zone centroid (computed). Lies in the tributary valley draining NW from the source to the border river (map flow arrows). Lake-1 to lake-2 straight-line distance 5.2 km (computed).", "verbatim_quote": "The second barrier lake, with an estimated area of approximately 19 ha, is located approximately 2 km west of the potential ice-rock avalanche source area, with the source area situated further east along the river channel.", "sweep_ref": "sweep-2026-09-11/A_entries.json[26]" }, { "id": "E-056", "item": "Lower (Puripu Qiangzangbu / Chhochen-Purepu confluence) barrier lake volume, 27 Aug morning", "value": 2, "unit": "million m3", "source_url": "https://www.globaltimes.cn/page/202608/1369172.shtml", "publisher": "Global Times (citing MWR via CCTV)", "published_date": "2026-08-27", "event_time": "2026-08-27", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "'estimated'", "use": "narrative_only", "notes": "Article continues: 'Another 3 million cubic meters of water is expected to flow into the lake over the next three days, posing a high risk of a breach'. Chinese original (Sina, MWR): '截至今天上午估算水量达到200万立方米，已经处于漫溢状态，未来3天预计还有300万立方米水将会入湖，溃泄风险高' (C_raw/cn_sina_0827_aerial.html). This is the post-event lower lake, NOT the 1.4 Mm3 crater. Raw: C_raw/gt_1369172.html", "verbatim_quote": "a significant barrier lake has formed near the confluence of the Chhochen Khola and Purepu Tsangpo rivers in Nepal, with its water volume estimated at 2 million cubic meters as of Thursday morning and the lake already overflowing.", "sweep_ref": "sweep-2026-09-11/C_entries.json[23]" }, { "id": "E-057", "item": "Lower barrier dam radar geometry and storage", "value": 2.2, "unit": "million m3; mean dam height 60 m; dam length ~1,100 m; mean width ~300 m; lake area ~0.1 km2", "source_url": "https://www.stdaily.com/web/gdxw/2026-09/05/content_575565.html", "publisher": "Science and Technology Daily (Xinhua; Xizang command HQ, Ren Wei)", "published_date": "2026-09-05", "event_time": null, "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "约 (about); date of radar survey not given", "use": "narrative_only", "notes": "Same numbers in Xinhua/ifeng 1 Sep (C_raw/cn_ifeng_mwr_expert.html). Refers to the lower lake above Gyirong Port core area. Raw: C_raw/cn_stdaily_0905.html", "verbatim_quote": "雷达探测显示，该堰塞体平均坝高60米，坝长约1100米，平均坝宽约300米，湖面面积约0.1平方公里，库容约220万方。", "sweep_ref": "sweep-2026-09-11/C_entries.json[30]" }, { "id": "E-058", "item": "Lower barrier lake 'basically drained' (30 Aug)", "value": "lower barrier lake basically drained (MWR)", "unit": null, "source_url": "https://english.news.cn/20260830/219b22b13e3b46d5a6a1f4152f998ed9/c.html", "publisher": "Xinhua (MWR)", "published_date": "2026-08-30", "event_time": "2026-08-30", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "High", "reported_precision_or_uncertainty": "qualitative", "use": "narrative_only", "notes": "Raw: C_raw/xinhua_0830_drained.html", "verbatim_quote": "The barrier lake above mudslide-hit Gyirong Port in southwest China's Xizang Autonomous Region has basically drained, forming a flowing state of the river channel, China's Ministry of Water Resources said Sunday, citing drone footage and panoramic images captured in the morning", "sweep_ref": "sweep-2026-09-11/C_entries.json[31]" }, { "id": "E-059", "item": "Lower barrier lake 'completely released' (1 Sep)", "value": "lower barrier lake completely released (Xizang command HQ)", "unit": null, "source_url": "https://dzrb.dzng.com/general/0/NEWS3634819CQMOKPDTKWSZQ", "publisher": "Xinhua via Dazhong Daily live blog (Xizang '8.26' command HQ)", "published_date": "2026-09-01", "event_time": "2026-09-01", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "High", "reported_precision_or_uncertainty": "qualitative", "use": "narrative_only", "notes": "", "verbatim_quote": "在西藏吉隆泥石流灾害过程中形成的普热普强藏布堰塞湖，目前已完全泄洪、风险可控。", "sweep_ref": "sweep-2026-09-11/C_entries.json[32]" }, { "id": "E-060", "item": "River rise from 28 Aug barrier-lake overflow", "value": 0.6, "unit": "m", "source_url": "https://www.aljazeera.com/news/2026/8/28/nepal-and-china-halt-rescue-efforts-as-border-barrier-lake-overflows", "publisher": "Al Jazeera (quoting Nepali Army spokesperson)", "published_date": "2026-08-28", "event_time": "2026-08-28", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Low-Medium", "reported_precision_or_uncertainty": "'just 0.6 metres (two feet)'; gauge/location not stated", "use": "narrative_only", "notes": "Secondary: Nepali Army spokesperson via Al Jazeera; no gauge location. No Chinese or DHM source found. A post-event secondary hazard, distinct from the modelled T+3 h pulse.", "verbatim_quote": "Nepal's army spokesperson said the rise in water level comprised just 0.6 metres (two feet).", "sweep_ref": "sweep-2026-09-11/C_entries.json[37]" }, { "id": "E-061", "item": "NDRRMA-reported lake area behind Lhende Khola blockage (Nepali original)", "value": 0.11, "unit": "km2", "source_url": "https://www.onlinekhabar.com/2026/08/2005190/lhende-river-lake-may-burst-high-alert-should-be-exercised-in-coastal-areas", "publisher": "OnlineKhabar (Nepali), reporting NDRRMA statement", "published_date": "2026-08-27", "event_time": "2026-08-27T11:44:00+05:45", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Medium", "reported_precision_or_uncertainty": "'करिब' (about); preliminary study", "use": "narrative_only", "notes": "Dateline 11 Bhadau (= 27 Aug 2026). Translation: per NDRRMA, preliminary study of Planet Labs and Landsat images RECEIVED at 11:44 this morning shows a lake of about 0.11 km2. 11:44 is receipt time, not necessarily acquisition time. Location: ~18 km upstream of Rasuwagadhi. No volume given by NDRRMA. Original NDRRMA notice itself not retrieved (NDRRMA site/X post would be needed). Raw: C_raw/np_ok_2005190.html", "verbatim_quote": "प्राधिकरणका अनुसार आज बिहान ११:४४ बजे प्राप्त प्लानेट ल्याब्स र ल्याण्डस्याटका स्याटेलाइट तस्वीरको विश्लेषणका आधारमा गरिएको प्रारम्भिक अध्ययनअनुसार उक्त क्षेत्रमा करिब ०.११ वर्गकिलोमिटर क्षेत्रफलको ताल बनेको देखिएको छ ।", "sweep_ref": "sweep-2026-09-11/C_entries.json[11]" }, { "id": "E-062", "item": "Nepal FFD (Parajuli): upper lake area and volume, 4 Sep", "value": 0.6, "unit": "million m3 (६ लाख घनमिटर); area ~0.19 km2", "source_url": "https://www.onlinekhabar.com/2026/09/2010703/the-lakes-above-the-lhende-river-are-no-longer-dangerous", "publisher": "OnlineKhabar (Nepali), quoting DHM Flood Forecasting Division chief Binod Parajuli relaying Chinese team", "published_date": "2026-09-04", "event_time": "2026-09-04", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Low-Medium", "reported_precision_or_uncertainty": "'करिब' (about); 'अनुमान' (estimate); level rise ~2 m", "use": "narrative_only", "notes": "Dateline 19 Bhadau (= 4 Sep). Same piece: Chinese team call the riverside lake 'Barrier Lake One' and the upper lake 'Barrier Lake Two'; pits formed after rock-ice fell. Conflicts with MWR 2 Sep 'crater drained'. Raw: C_raw/np_ok_2010703.html", "verbatim_quote": "माथिल्लो भागमा रहेको ताल करिब शून्य दशमलव १९ वर्गकिलोमिटरको हो । त्यो तालमा दुई मिटर सतह बढेर करिब ६ लाख घनमिटर पानी जम्मा भएको अनुमान छ ।", "sweep_ref": "sweep-2026-09-11/C_entries.json[20]" }, { "id": "E-063", "item": "New landslide-dammed lake 2.8 km downstream of Puripu lake (29 Aug), breached", "value": 2.8, "unit": "km downstream of Puripu Qiangzangbu barrier lake", "source_url": "https://tidenews.com.cn/news.html?id=3544355", "publisher": "Tide News (MWR citing Ministry of Emergency Management)", "published_date": "2026-08-30", "event_time": "2026-08-29", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "qualitative", "use": "narrative_only", "notes": "A third, short-lived post-event impoundment. Xinhua English 30 Aug carries same.", "verbatim_quote": "8月29日应急管理部反馈，普热普强藏布堰塞湖下游2.8公里处，因尼泊尔侧滑坡形成一处新的堰塞湖。根据无人机视频和全景影像分析，目前堰塞体已被上游来水冲开", "sweep_ref": "sweep-2026-09-11/C_entries.json[33]" }, { "id": "E-064", "item": "CLaSH: two post-event lakes (major axes)", "value": 770, "unit": "m (lower lake major axis); 530 m (upper lake major axis)", "source_url": "https://storymaps.arcgis.com/stories/f2b2425eac544929a7d18f4c90b41d66", "publisher": "Center for Land Surface Hazards (CLaSH), NSF-funded; ArcGIS StoryMap", "published_date": "2026-09-02", "event_time": "2026-08-28", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "'approximately'", "use": "narrative_only", "notes": "Coordinates: lower 28.332916N 85.482467E; upper 28.292884N 85.510942E (Planet imagery 28 Aug). CLaSH also states the lakes 'formed substantially after the ice-rock avalanche'. Upper lake is ~5.3 km straight-line from lower lake (cf. MWR 5.6 km) and ~0.4 km from DHM's avalanche coordinate. Raw: C_raw/storymap_data.json", "verbatim_quote": "One of the lakes, measuring approximately 770 meters along its major axis, formed within the Lhende Khola River bank. The other, measuring approximately 530 meters along its major axis, formed just below the collapsed glacier.", "sweep_ref": "sweep-2026-09-11/C_entries.json[16]" }, { "id": "E-065", "item": "Chinese scientist: no barrier lake in the original (main) process", "value": "no barrier lake in the original process; the lake formed later behind a small adjacent landslide", "unit": null, "source_url": "https://www.wenweipo.com/a/202608/29/AP6a91f0b1e4b0c1e50026a49a.html", "publisher": "Wen Wei Po quoting Xu Qiang (President, Chengdu University of Technology)", "published_date": "2026-08-29", "event_time": "2026-08-28", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Medium", "reported_precision_or_uncertainty": "expert statement", "use": "narrative_only", "notes": "Translation: the ice avalanche broke up directly into a debris flow; in the original process there was actually no barrier lake; the barrier lake was produced when a small adjacent landslide blocked the channel. Directly contradicts IRDR/ADRC dam-breach mechanism.", "verbatim_quote": "冰崩直接破碎解體轉化成泥石流，在原來的發生過程中實際上沒有堰塞湖。堰塞湖的產生是由旁邊的小滑坡堵塞河道，產生積水河道，最後形成的堰塞湖。", "sweep_ref": "sweep-2026-09-11/C_entries.json[35]" }, { "id": "E-066", "item": "No moraine lakes >0.1 km2 on Nepal side above Gyirong Port", "value": 0, "unit": "count (Nepal side); 13 on Chinese side", "source_url": "https://tidenews.com.cn/news.html?id=3544355", "publisher": "Tide News (MWR)", "published_date": "2026-08-30", "event_time": null, "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "threshold 0.1 km2", "use": "narrative_only", "notes": "The 13 Chinese-side lakes showed little area change over the past month (argues against a GLOF source).", "verbatim_quote": "吉隆藏布流域吉隆口岸以上尼泊尔侧未发现面积大于0.1平方千米的冰碛湖；中方侧共有13个面积大于0.1平方千米的冰碛湖", "sweep_ref": "sweep-2026-09-11/C_entries.json[36]" }, { "id": "E-067", "item": "Nepal FFD (Parajuli): lake water ~10% of main flood water (27 Aug)", "value": 10, "unit": "% of Wednesday's flood water", "source_url": "https://english.onlinekhabar.com/new-lake-rasuwa-fact.html", "publisher": "OnlineKhabar English, quoting Binod Parajuli (DHM FFD)", "published_date": "2026-08-27", "event_time": "2026-08-27", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Low", "reported_precision_or_uncertainty": "'around'; basis not stated", "use": "narrative_only", "notes": "Same article attributes MWR's 2 Mm3 (lower, confluence lake) to 'the depression' below the avalanche - a conflation of the lower barrier lake with the upper impact pit in early reporting. Raw: C_raw/ok_new_lake_fact.html", "verbatim_quote": "According to him, the amount of water currently accumulated in the lake is only around 10 percent of the water involved in Wednesday's flood.", "sweep_ref": "sweep-2026-09-11/C_entries.json[21]" }, { "id": "E-068", "item": "Lower barrier lake storage >2.5 Mm3 (CCTV, 28 Aug)", "value": 2.5, "unit": "million m3 (lower bound)", "source_url": "https://www.globaltimes.cn/page/202608/1369273.shtml", "publisher": "Global Times (citing CCTV News)", "published_date": "2026-08-28", "event_time": "2026-08-28", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Low-Medium", "reported_precision_or_uncertainty": "'more than'", "use": "narrative_only", "notes": "Same article: lake ~1,000 m above Gyirong Port. Conflicts in trend with MWR area decreasing since 27 Aug 13:00. Raw: C_raw/gt_1369273.html", "verbatim_quote": "The water area of the barrier lake continues to expand, with unstable landslide masses visible on both sides, and is currently estimated to hold more than 2.5 million cubic meters of water.", "sweep_ref": "sweep-2026-09-11/C_entries.json[28]" }, { "id": "E-069", "item": "Lower barrier lake maximum storage (China Anneng expert)", "value": 4, "unit": "million m3 (max, 27 Aug); >2.5 million m3 (28 Aug afternoon)", "source_url": "https://news.qq.com/rain/a/20260829A01CMH00", "publisher": "CCTV 'News 1+1' (China Anneng 3rd Bureau chief expert Zhou Zhidong)", "published_date": "2026-08-29", "event_time": "2026-08-27", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Low-Medium", "reported_precision_or_uncertainty": "'最大库容' maximum; '250多万' 2.5+ million", "use": "narrative_only", "notes": "'Yesterday'/'today' interpreted as 27/28 Aug (programme = rescue day three, posted 29 Aug 01:47). Contradicts MWR 27 Aug morning estimate of 2 Mm3.", "verbatim_quote": "昨天堰塞湖最大库容为400万立方米，到今天下午已经降至250多万立方米。", "sweep_ref": "sweep-2026-09-11/C_entries.json[29]" }, { "id": "E-070", "item": "Seismic-inversion source volume (regional stations)", "value": "284-492", "unit": "Mm3 bulk source volume", "source_url": "https://storymaps.arcgis.com/stories/f2b2425eac544929a7d18f4c90b41d66", "publisher": "CLaSH StoryMap (analysis/figure by Christopher Calvelage, EarthScope)", "published_date": "2026-09-02", "event_time": "2026-08-26T08:37:10+05:45", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Low-Medium", "reported_precision_or_uncertainty": "range from two Earth models; empirical force-volume scaling (Ekstrom & Stark 2013; Chao et al. 2016); preliminary", "use": "narrative_only", "notes": "BULK SOURCE VOLUME from a long-period seismic force inversion (regional stations), not peer-reviewed, bulk density 2,200 kg/m3. Not a water volume. A new ensemble member based on it is approval-gated.", "verbatim_quote": "Assuming a bulk density of 2200 kg/m3, the regional and teleseismic solutions give 284-492 and 197-349 Mm3 respectively (panel c).", "sweep_ref": "sweep-2026-09-11/C_entries.json[58]" }, { "id": "E-071", "item": "Seismic-inversion source volume (teleseismic stations)", "value": "197-349", "unit": "Mm3 bulk source volume", "source_url": "https://storymaps.arcgis.com/stories/f2b2425eac544929a7d18f4c90b41d66", "publisher": "CLaSH StoryMap (Christopher Calvelage, EarthScope)", "published_date": "2026-09-02", "event_time": "2026-08-26T08:37:10+05:45", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Low-Medium", "reported_precision_or_uncertainty": "as above", "use": "narrative_only", "notes": "", "verbatim_quote": "using the global teleseismic stations results in an estimated volume of 197-349 million cubic meters", "sweep_ref": "sweep-2026-09-11/C_entries.json[59]" }, { "id": "E-072", "item": "ICIMOD cryosphere specialist estimate of collapse size", "value": "100-200", "unit": "Mm3 collapse size (quantity type not stated)", "source_url": "https://kathmandupost.com/national/2026/08/28/what-triggered-the-rasuwa-flood-scientists-piece-together-a-complex-chain-of-events", "publisher": "The Kathmandu Post quoting Dr Mohd. Farooq Azam (ICIMOD)", "published_date": "2026-08-28", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Low", "reported_precision_or_uncertainty": "range; basis not stated", "use": "narrative_only", "notes": "Named ICIMOD scientist; method not given.", "verbatim_quote": "The glacier collapse was 100 to 200 million cubic meters in size and hit the valley 1000 meters below,", "sweep_ref": "sweep-2026-09-11/C_entries.json[61]" }, { "id": "E-073", "item": "Tribhuvan University (Dahal) conservative satellite-based estimate", "value": 25, "unit": "million m3 (up to 40; others up to 100)", "source_url": "https://english.onlinekhabar.com/ice-mass-bhotekoshi-flood.html", "publisher": "OnlineKhabar English quoting Prof Ranjan Kumar Dahal (TU)", "published_date": "2026-09-02", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Low", "reported_precision_or_uncertainty": "'very conservative'; dimensions 1.3 km long, 500-800 m wide, ~60-70 m thick", "use": "narrative_only", "notes": "Raw: C_raw/fm_ok_ice_mass_25Mm3.html", "verbatim_quote": "Even using a very conservative estimate based on satellite data, around 25 million cubic metres of snow and ice appear to have fallen,", "sweep_ref": "sweep-2026-09-11/C_entries.json[62]" }, { "id": "E-074", "item": "CU Boulder Today: 50 million metric tons of ice, rock and water (earliest instance found)", "value": 50, "unit": "million metric tons (equated to ~13 billion US gallons)", "source_url": "https://www.colorado.edu/today/2026/09/03/how-warming-might-have-caused-nepals-deadly-floods", "publisher": "CU Boulder Today (university news Q&A with Alton Byers, INSTAAR)", "published_date": "2026-09-03", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "tertiary", "confidence": "Low", "reported_precision_or_uncertainty": "'An estimated'; estimator not named", "use": "narrative_only", "notes": "FAILURE MASS, tertiary, unattributed; internally inconsistent (equates 50 Mt with water density). Traced from Britannica (uncited) to CU Boulder Today; no technical primary found.", "verbatim_quote": "An estimated 50 million metric tons of ice, rock and water—roughly 13 billion gallons, or about three times the capacity of Boulder Reservoir—fell 6,500 feet into the valley below", "sweep_ref": "sweep-2026-09-11/C_entries.json[57]" }, { "id": "E-075", "item": "Britannica failure mass", "value": 55, "unit": "million short tons (about 50 million metric tons) of ice and rock", "source_url": "https://web.archive.org/web/20260909195450/https://www.britannica.com/event/Nepal-floods-of-2026", "publisher": "Encyclopaedia Britannica (John P. Rafferty); read via Wayback 2026-09-09", "published_date": null, "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "tertiary", "confidence": "Low", "reported_precision_or_uncertainty": "none stated; no citation", "use": "narrative_only", "notes": "No source given. Live page 403; archived copy at https://web.archive.org/web/20260909195450/https://www.britannica.com/event/Nepal-floods-of-2026. Raw: C_raw/britannica_wayback.html", "verbatim_quote": "Others, however, suggested that this cascade of 55 million tons (about 50 million metric tons) of ice and rock developed into a fast moving surge of water, sediment, melting ice, and debris.", "sweep_ref": "sweep-2026-09-11/C_entries.json[56]" }, { "id": "E-076", "item": "Geopera model-calibrated flow volume", "value": 100, "unit": "million m3 (±40%)", "source_url": "https://geopera.com/blog/bhote-koshi-flood-2026-satellite-analysis", "publisher": "Geopera blog (Darcy Weedman)", "published_date": "2026-08-28", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "tertiary", "confidence": "Low", "reported_precision_or_uncertainty": "give or take 40%", "use": "narrative_only", "notes": "FLOW VOLUME from a model calibrated to the Galchhi stage rise; not a failure mass and not independent of the gauge observation. Tertiary.", "verbatim_quote": "One volume satisfies both at once: about 100 million cubic metres, give or take 40%.", "sweep_ref": "sweep-2026-09-11/C_entries.json[65]" }, { "id": "E-077", "item": "UNOSAT detachment zone (Landsat-9, 26 Aug 2026)", "value": "1.957 (GDB Area_m2 1,956,822.875; geodesic 1,957,373 m2)", "unit": "km2", "source_url": "https://unosat.org/static/unosat_filesystem/4260/FL20260826NPL.gdb.zip", "publisher": "UNOSAT (UNITAR)", "published_date": "2026-08-31", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "Attribute SensorDate reads 2026/09/26 (implausible/future date; layer name says 20260826) - attribute error.", "use": "narrative_only", "notes": "Layer UNOSAT_Landsat9_20260826_DetachmentZone; centroid 85.52132E, 28.28913N; bbox 85.5109-85.5299E, 28.2822-28.2958N. Map legend: \"Detachment zone [26 Aug. 2026]\"; \"Ice-rock avalanche possible triggering location\" symbol at its east end.", "verbatim_quote": "", "sweep_ref": "sweep-2026-09-11/A_entries.json[28]" }, { "id": "E-078", "item": "Relation of 2026 source to 2025 source (HiRISK NP3)", "value": "2026: rock-ice detachment of glacier RGI2000-v7.0-G-15-05732 north of Lirung massif, Lhende catchment, 28.288708°N 85.528159°E, ~5200 m; mass flow met 2025 Purepu GLOF deposits on valley floor <3000 m and dammed Lhende Khola", "unit": "qualitative; decimal degrees; m", "source_url": "https://hirisk.org/wp-content/uploads/2026/08/RHA_NP3_RasuwaFlood.pdf", "publisher": "HiRISK RHA Report No. NP3 (Q. Liu, A. Khatri, A. Lord, M. Ghouli, N. Thapa, J. Steiner, W.W. Immerzeel, S. Allen)", "published_date": "2026-08-28", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "rapid assessment; 'approximately'", "use": "narrative_only", "notes": "Same Lhende (Lende) catchment and same downstream corridor, but DIFFERENT glacier and sub-catchment: computed straight-line distance Purepu lake (28.402561, 85.646705) to 2026 source point = 17.2 km; 2026 source to Rasuwagadhi = 14.7 km. ICIMOD page summarising Qianggong Zhang interview: 2026 avalanche 'originated inside Nepali territory' (2025 source was in China). NP3 internal time inconsistency: '08:37 am NPT ... (10: 52 am CST)' vs '8:37 am Nepal local time (10:59 am Beijing time)'; 08:37 NPT = 10:52 CST.", "verbatim_quote": "Here the mass flow met with deposits from the Purepu GLOF event in 2025 (Zhang et al., 2026) and caused the Lhende Khola to dam, potentially only for a matter of minutes.", "sweep_ref": "sweep-2026-09-11/D_entries.json[28]" }, { "id": "E-080", "item": "USGS inundation-boundary mapping status", "value": "underway (stated); no downloadable boundary dataset linked from page as of last update 8/28/2026", "unit": null, "source_url": "https://web.archive.org/web/20260910230007/https://www.usgs.gov/programs/landslide-hazards/science/2026-nepal-debris-avalanche-and-flash-flood", "publisher": "USGS Landslide Hazards Program", "published_date": "2026-08-27", "event_time": null, "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "Page states page will no longer be updated after the response.", "use": "narrative_only", "notes": "Live usgs.gov returned CloudFront 403 / AWS-WAF JS challenge (HTTP 202) to curl and empty content to WebFetch on 2026-09-11; text taken from Internet Archive capture 20260910230007 (id_ raw), saved as A_raw/usgs_page_wb_20260910230007.html. The page and linked media page list no data release / shapefile; ScienceBase catalog queries (\"Nepal 2026 debris\", \"Langtang\") returned 0 items on 2026-09-11. Only a static map image is published (see next entry).", "verbatim_quote": "USGS geologists are mapping the inundation boundary of the debris flow and flood by using satellite imagery.", "sweep_ref": "sweep-2026-09-11/A_entries.json[7]" }, { "id": "E-081", "item": "UNOSAT Product 4260 identity", "value": "ID 4260; \"Satellite-Detected Newly Formed Barrier Lakes Following an Ice-Rock Avalanche in Rasuwa District, Nepal, as of 28 August 2026\"; GLIDE FL20260826NPL", "unit": null, "source_url": "https://unosat.org/products/4260", "publisher": "UNOSAT (UNITAR)", "published_date": "2026-08-31", "event_time": "2026-08-28", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "API created_at 2026-08-31T13:55:17Z; PDF CreationDate 2026-08-31. BUT map header reads \"IMAGERY ANALYSIS: 26&27/08/2026 PUBLISHED 27/08/2026 V1.\" (apparently carried over from Product 4257 template).", "use": "narrative_only", "notes": "unosat.org is a JS SPA; data retrieved from its JSON backend https://unosat.org/our_products/4260 (Accept: application/json). unitar.org/maps/map/4260 returned 404. Map JPG https://unosat.org/static/unosat_filesystem/4260/Barrier_Lake_Map1.jpg ; PDF https://unosat.org/static/unosat_filesystem/4260/UNOSAT_BarrierLakes_Nepal_China_v1.pdf. Both 28-Aug Cartosat inset panels are labelled \"BEFORE\" (labelling error).", "verbatim_quote": "Satellite-Detected Newly Formed Barrier Lakes Following an Ice-Rock Avalanche in Rasuwa District, Nepal, as of 28 August 2026", "sweep_ref": "sweep-2026-09-11/A_entries.json[24]" }, { "id": "E-082", "item": "UNOSAT GDB FloodExtent layer area (cumulative floodwater/mudflow/rockflow, 26-28 Aug)", "value": "64.9 (geodesic; attribute Area_m2 65,660,992)", "unit": "km2", "source_url": "https://unosat.org/static/unosat_filesystem/4260/FL20260826NPL.gdb.zip", "publisher": "UNOSAT (UNITAR)", "published_date": null, "event_time": "2026-08-26/2026-08-28", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "Area_ha attribute wrongly equals Area_m2 value. Single class; does not separate water from debris. Includes both barrier-lake polygons.", "use": "narrative_only", "notes": "Derived by agent A (A_raw/derived_unosat_gdb_measurements.txt). bbox 84.3558-85.5299E, 27.6776-28.3405N; analysis extent 1,245.6 km2. Portion north of 28.25N: 16.9 km2; 27.9-28.25N: 14.3 km2; south of 27.9N: 33.7 km2 (downstream reach far below 100 km USGS figure, likely includes Trishuli floodwater).", "verbatim_quote": "", "sweep_ref": "sweep-2026-09-11/A_entries.json[30]" }, { "id": "E-083", "item": "Copernicus EMS Rapid Mapping activation EMSR927", "value": "activated 2026-08-26T09:53; eventTime listed 2026-08-25T22:00; activator EC Services / DG ECHO; category Flood / Flash flood; Charter 1052; GDACS FL1104124", "unit": null, "source_url": "https://rapidmapping.emergency.copernicus.eu/backend/dashboard-api/public-activations/?code=EMSR927", "publisher": "Copernicus EMS (European Commission)", "published_date": "2026-08-26", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "Times as served (timezone not stated in API; presumably UTC). eventTime 2026-08-25T22:00 precedes the ComCat signal (02:52 UTC 26 Aug) - likely an approximate/placeholder value.", "use": "narrative_only", "notes": "Observed-event layer is a mass-movement / debris extent, not flood-water extent.", "verbatim_quote": "On the 26 August 2026, a flash flood reportedly triggered by a Glacial Lake Outburst Flood (GLOF) in Nepal has caused significant damage in Rasuwa District. There is a 7 m-deep water level recorded by monitoring stations.", "sweep_ref": "sweep-2026-09-11/A_entries.json[34]" }, { "id": "E-084", "item": "Sentinel Asia: JAXA ALOS-2 Flood Proxy Map", "value": "SAR flood-extent proxy from ALOS-2 acquisition 2026-08-28 (file stamp 202608280620); GeoJSON + shapefile; posted 2026-08-31", "unit": null, "source_url": "https://sentinel-asia.org/EO/2026/article20260826NP/JAXA/JAXA_20250828_FPM_ALOS2_Nepal_FLDEXT.zip", "publisher": "JAXA via Sentinel Asia", "published_date": "2026-08-31", "event_time": "2026-08-28", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "Automatic analysis; zip filename says 20250828 (typo) but content file 2026-00033-WLD_202608280620_FLDEXT.geojson.", "use": "narrative_only", "notes": "Represents flood-water proxy (SAR change), not debris extent. Downloaded to A_raw/sa/JAXA_FPM.zip; not analysed further.", "verbatim_quote": "Flood Proxy Map 2026-08-28 by ALOS-2 (Automatic Analysis)", "sweep_ref": "sweep-2026-09-11/A_entries.json[43]" }, { "id": "E-085", "item": "Charter narrative: surge onset time at Bhote Koshi (Tibet side)", "value": "approximately 09:15 local time (NPT) on 26 Aug 2026", "unit": "NPT", "source_url": "https://disasterscharter.org/activations/flood-in-nepal-activation-1052-", "publisher": "International Charter Space and Major Disasters", "published_date": "2026-08-26", "event_time": "2026-08-26T03:30Z", "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "Low-Medium", "reported_precision_or_uncertainty": "\"approximately\"; compiled narrative, source of time not given. ~38 min after ComCat primary signal (08:37:10 NPT).", "use": "narrative_only", "notes": "ICIMOD press release instead says water levels began rising \"around 9:00 AM local time\" (local reports).", "verbatim_quote": "On 26 August 2026, a major flash flood struck Rasuwa District in northern Nepal after a sudden and intense surge of water entered the Bhote Koshi River from the Tibet (China) side at approximately 9:15 AM local time.", "sweep_ref": "sweep-2026-09-11/A_entries.json[40]" }, { "id": "E-090", "item": "2025 trigger: official Nepal attribution (NDRRMA)", "value": "Rapid discharge/outburst of supraglacial lake on Purepu Glacier; at least part supraglacial drainage", "unit": "qualitative", "source_url": "https://www.dpnet.org.np/uploads/files/Rasuwagadhi_Flood_Sitrep1_08072025_%202026-01-20%2009-22-38.pdf", "publisher": "Government of Nepal, NDRRMA Situation Report #1", "published_date": "2025-07-10", "event_time": null, "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "remote-sensing based; sources DHM and ICIMOD cited in report", "use": "narrative_only", "notes": "Report also states ponds formed 'Beginning in March 2025', ~0.525 km² by 28 June (source: ICIMOD), ~0.75 km² by 07 July (source: DHM).", "verbatim_quote": "On 08 July, the lake had undergone a rapid decline in area, shrinking to approximately 0.6 km² (source :DHM). Drainage features visible on the glacier surface that day indicate that at least part of the outburst occurred supraglacially", "sweep_ref": "sweep-2026-09-11/D_entries.json[8]" }, { "id": "E-091", "item": "2025 trigger: peer-reviewed confirmation (field + remote sensing)", "value": "Supraglacial GLOF from Purepu Glacier lake on 8 July 2025; outflow initially over glacier surface then gorge", "unit": "qualitative", "source_url": "https://doi.org/10.1016/j.accre.2026.06.022", "publisher": "Zhang T.-G., Wang W.-C., Khadka N., ... Yao T.-D., Advances in Climate Change Research (Elsevier/KeAi), doi:10.1016/j.accre.2026.06.022", "published_date": null, "event_time": "2025-07-08", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "field surveys, remote sensing, resident interviews", "use": "narrative_only", "notes": "Abstract retrieved via OpenAlex (full text 403 at ScienceDirect). Crossref issue 2026-06; DOI registered 2026-06-29. Mechanisms proposed include 'perturbed englacial drainage networks ... and powerful hydrofracturing'.", "verbatim_quote": "On 8 July 2025, a second supraglacial GLOF occurred on the Purepu Glacier, located 16 km northwest of Nielangpu. ... The high-energy outflow initially traveled over the glacier surface and a downstream gorge", "sweep_ref": "sweep-2026-09-11/D_entries.json[11]" }, { "id": "E-092", "item": "2025 trigger caveat: incomplete drainage and possible englacial/subglacial contribution", "value": "2025 drainage incomplete; englacial/subglacial contributions 'cannot be excluded'", "unit": "qualitative", "source_url": "https://egusphere.copernicus.org/preprints/2026/egusphere-2026-4065/egusphere-2026-4065.pdf", "publisher": "Xu Q., Kang S., Du W., et al., EGUsphere preprint egusphere-2026-4065 (Brief communication; not yet peer reviewed)", "published_date": "2026-08-12", "event_time": null, "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "Medium", "reported_precision_or_uncertainty": "preprint under discussion", "use": "narrative_only", "notes": "Also documents a satellite-inferred 2023 drainage of same lake system constrained to 12-15 July 2023, and residual water into 2026 (0.212 ± 0.032 km² on 25 June 2026, Sentinel-2).", "verbatim_quote": "The 2025 event remained incomplete, and flood-volume reconstruction suggests additional englacial or subglacial contributions cannot be excluded.", "sweep_ref": "sweep-2026-09-11/D_entries.json[13]" }, { "id": "E-093", "item": "2025 Lende/Bhote Koshi flood: first reported impact time at Rasuwagadhi border post", "value": "2025-07-08 03:15 NPT (05:30 China Standard Time)", "unit": "local time", "source_url": "https://hirisk.org/wp-content/uploads/2025/07/RHA_CN1_PurepuGLOF-2.pdf", "publisher": "HiRISK (Qiao Liu, Amrit Thapa, Jakob Steiner), Rapid Hazard Assessment Report No. CN1", "published_date": "2025-07-09", "event_time": "2025-07-08T03:15:00+05:45", "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "High", "reported_precision_or_uncertainty": "Impact time from reports; lake-drainage local time explicitly 'Unknown'", "use": "narrative_only", "notes": "Same time given by Stimson (Lord, 2025): '3:15 a.m. Nepal time (5:30 a.m. Beijing time)'. Xu et al. 2026 preprint only says 'early on 8 July 2025' citing DPNet sitrep. Chinese media: 'around 5 a.m.' (Sixth Tone) / '5时许' (The Paper). A '05时45分' time appears only in tertiary Chinese aggregator text (Baidu/163) and was NOT verified.", "verbatim_quote": "Local time: Unknown (first reported impact, 0530CST/0315 NPT)", "sweep_ref": "sweep-2026-09-11/D_entries.json[0]" }, { "id": "E-094", "item": "2025 source lake coordinates and elevation (HiRISK)", "value": "28.402561°N, 85.646705°E; 5160 m a.s.l.", "unit": "decimal degrees; m a.s.l.", "source_url": "https://hirisk.org/wp-content/uploads/2025/07/RHA_CN1_PurepuGLOF-2.pdf", "publisher": "HiRISK RHA CN1", "published_date": "2025-07-09", "event_time": null, "accessed_date": "2026-09-11", "source_tier": "near_primary", "confidence": "High", "reported_precision_or_uncertainty": "point location of lake; lake formation ~5100 m 'midway of the glacier tongue'", "use": "narrative_only", "notes": "Nepali-language page of same report has a longitude typo (86.402561). DHM coordinates (28.4043, 85.6469) differ by ~0.19 km (computed). Straight-line distance lake->Rasuwagadhi (28.27875, 85.37808, Petley) computed = 29.7 km; along-valley distances reported: 35 km (HiRISK, Stimson, NDRRMA), 36 km (DHM), ~31 km to Friendship Bridge (Xu et al. 2026).", "verbatim_quote": "Location: supraglacial lake, Purepu Glacier, Lendhe Catchment, Bhote Koshi Country: China (transboundary to Nepal) Lat: 28.402561°N - Lon: 85.646705°E - Elevation: 5160 m a.s.l.", "sweep_ref": "sweep-2026-09-11/D_entries.json[5]" }, { "id": "E-095", "item": "2025 damage summary (NDRRMA, as of 10 July 2025)", "value": "Friendship (Miteri) Bridge destroyed; Rasuwagadhi dry port damaged; 3 hydropower plants; 16 km road", "unit": "counts; km", "source_url": "https://www.dpnet.org.np/uploads/files/Rasuwagadhi_Flood_Sitrep1_08072025_%202026-01-20%2009-22-38.pdf", "publisher": "Government of Nepal, NDRRMA Situation Report #1", "published_date": "2025-07-10", "event_time": "2025-07-08", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "as of 10 July 2025 (human-impact counts redacted by policy)", "use": "narrative_only", "notes": "Human-impact counts removed by policy; infrastructure items only.", "verbatim_quote": "Notable losses include the Nepal - China Friendship Bridge at Rasuwagadhi, large sections of the Rasuwagadhi dry port, and three hydropower plants on the catchment area.", "sweep_ref": "sweep-2026-09-11/D_entries.json[23]" }, { "id": "E-096", "item": "2025 published gauge hydrographs at Galchhi, Malekhu, Betrawati, Syabrubesi", "value": "NOT FOUND", "unit": "availability", "source_url": "https://dhm.gov.np/hydrology/river-watch", "publisher": "Department of Hydrology and Meteorology (DHM), river-watch portal", "published_date": null, "event_time": "2025-07-08", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Qualitative", "reported_precision_or_uncertainty": "n/a", "use": "narrative_only", "notes": "Station metadata extracted from portal HTML (D_raw/dhm_station_metadata_extract_20260911.txt). Portal endpoint https://dhm.gov.np/site/getRiverWatchBySeriesId_Single returned empty series for 2025-07-07/08/09 for Betrawati (series 943), Galchi (36628), Shyaprubesi (2810), Rasuwagadi (23251) and Bahrabise control, but returned data for 2026-08-26 -> public retention window is short. No 'Malekhu' station in river-watch list. 2025 series would need a DHM data request (https://dhm.gov.np/pages/data). No news/agency source with 2025 Galchhi/Betrawati/Malekhu timing was verified.", "verbatim_quote": "{\"name\":\"Bhotekoshi at Rasuwagadi\",\"id\":4913,\"stationIndex\":\"446.22\",\"basin\":\"Narayani\",\"district\":\"Rasuwa\",\"latitude\":28.271297,\"longitude\":85.377649", "sweep_ref": "sweep-2026-09-11/D_entries.json[25]" }, { "id": "E-097", "item": "2025 availability: DHM Flood Report 2082 annex - 8 Jul 2025 preliminary report (issued 2082/03/24 10:00)", "value": "Timure hydropower gauge +~3.5 m at 03:10; Syaphrubesi 3.65 m @03:30 -> 5.37 m @03:40 then transmission stopped; Betrawati 1.60 m (~220 m3/s) @05:00 -> 3.63 m @05:10, max 4.18 m (~1600 m3/s) @05:50 NPT", "unit": null, "source_url": "https://hydrology.gov.np/cm/files/Flood_Report_2082_1778213668085.pdf", "publisher": "DHM Flood Forecasting Division", "published_date": "2026-05-08", "event_time": "2025-07-08T03:10:00+05:45", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "10-min values as stated by DHM; flood entry 'around 3 AM'", "use": "narrative_only", "notes": "Annex ङ (PDF pp.165-166) reproduces the report with two small hydrograph screenshots (Timure hydropower gauge, 1640-1645 m scale; Syaphrubesi 01:50-03:40). SMS alert issued 06:30. Original 8 Jul 2025 PDF not found in hydrology.gov.np notice list.", "verbatim_quote": "रसुवागढी नाकाबाट करिब १३ किलोमिटर तल यस विभागको रसुवा स्थित स्याप्रुवेसी स्वचालित जलमापन केन्द्रमा विहान ३:३० बजे एक्कासी बहाव बढेको देखिन्छ।", "sweep_ref": "sweep-2026-09-11/B_entries.json[57]" }, { "id": "E-098", "item": "ICIMOD statement linking 2026 event site to 2025 flood", "value": "'The same site devastated by last year's Rasuwa flood'", "unit": "qualitative", "source_url": "https://www.icimod.org/press-release/major-flash-flood-sweeps-through-nepals-rasuwa-district-raising-fears-of-further-downstream-flooding/", "publisher": "ICIMOD media advisory, 26 Aug 2026 (quote: Qianggong Zhang)", "published_date": "2026-08-26", "event_time": "2026-08-26", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Qualitative", "reported_precision_or_uncertainty": "n/a", "use": "narrative_only", "notes": "Refers to impacted corridor (Rasuwagadhi/Lhende Khola), not same source glacier. Same advisory: 'The Lhende Khola has flooded twice in fourteen months' (Saswata Sanyal).", "verbatim_quote": "“The same site devastated by last year’s Rasuwa flood is once again under threat,” said Qianggong Zhang, Head of Climate and Environmental Risks at ICIMOD.", "sweep_ref": "sweep-2026-09-11/D_entries.json[29]" }, { "id": "E-099", "item": "KP 28 Aug: DHM & ICIMOD supraglacial-lake GLOF attribution refers to JULY 2025 event", "value": "the supraglacial-lake GLOF attribution in this article refers to July 2025", "unit": null, "source_url": "https://kathmandupost.com/national/2026/08/28/what-triggered-the-rasuwa-flood-scientists-piece-together-a-complex-chain-of-events", "publisher": "The Kathmandu Post (Subeksha Poudel)", "published_date": "2026-08-28", "event_time": null, "accessed_date": "2026-09-11", "source_tier": "secondary", "confidence": "High", "reported_precision_or_uncertainty": "n/a", "use": "narrative_only", "notes": "Resolves the 2025/2026 ambiguity: the DHM/ICIMOD supraglacial-lake attribution in this article refers to the July 2025 event. Not imported as 2026 mechanism evidence.", "verbatim_quote": "Flooding in the same Bhotekoshi River exactly a year ago in July had also left scientists searching for answers... The Department of Hydrology and Meteorology and ICIMOD later concluded, based on satellite imagery, that the flooding was due to GLOF from a supraglacial lake", "sweep_ref": "sweep-2026-09-11/C_entries.json[46]" }, { "id": "E-100", "item": "USGS statement on 2015 Gorkha-earthquake debris avalanche from same mountain", "value": "several million cubic metres of ice and debris; start ~5,000 m elevation; fell ~1,900 m", "unit": null, "source_url": "https://web.archive.org/web/20260910230007/https://www.usgs.gov/programs/landslide-hazards/science/2026-nepal-debris-avalanche-and-flash-flood", "publisher": "USGS Landslide Hazards Program", "published_date": "2026-08-27", "event_time": "2015-04-25", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "Medium", "reported_precision_or_uncertainty": "Order-of-magnitude only (\"several million\"); elevations not verified here against peer-reviewed sources.", "use": "narrative_only", "notes": "USGS says 'this mountain', not the same slope: the 2015 deposit is in the Langtang valley; the 2026 detachment drains north-west to the Lende Khola.", "verbatim_quote": "This mountain was previously the source of another large debris avalanche in 2015 caused by a M7.8 earthquake. There, several million cubic meters of ice and debris collapsed, starting at 5,000-meter elevation, and fell nearly 1,900 meters, burying a village, and [… human-impact text redacted by policy]", "sweep_ref": "sweep-2026-09-11/A_entries.json[12]" }, { "id": "E-101", "item": "2015 Langtang avalanche: DEM-derived deposit volume (Fujita et al. 2017)", "value": "6.81 ± 1.54 × 10^6 m³ (primary event); 0.84 ± 0.92 × 10^6 m³ (succeeding rockfalls)", "unit": "m³", "source_url": "https://doi.org/10.5194/nhess-17-749-2017", "publisher": "Fujita K. et al., Natural Hazards and Earth System Sciences 17:749-764", "published_date": "2017-05-22", "event_time": "2015-04-25", "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "± as reported", "use": "narrative_only", "notes": "'106' = 10^6 (superscript lost in text extraction). Primary event 'an avalanche composed mostly of snow'; source-area snow depth 1.82 ± 0.46 m.", "verbatim_quote": "Multitemporal digital elevation models ... reveal that the deposit volumes of the primary and succeeding events were 6.81 ± 1.54 × 106 and 0.84 ± 0.92 × 106 m3 , respectively.", "sweep_ref": "sweep-2026-09-11/D_entries.json[43]" }, { "id": "E-110", "item": "Costa & Schuster (1988) landslide-dam peak discharge regression", "value": "Q = 0.0158 (PE)^0.41", "unit": "Q in m³/s; PE in joules", "source_url": "https://hydroschool.org/wp-content/uploads/2024/10/i0016-7606-100-7-1054.pdf", "publisher": "Costa J.E. & Schuster R.L., GSA Bulletin 100(7):1054-1068 (Table 6)", "published_date": "1988-07", "event_time": null, "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "n = 12 landslide dams; r² = 0.81; standard error 185%", "use": "narrative_only", "notes": "Verified from scanned original (page 1065, rendered image). Candidate formula coefficient/exponent CONFIRMED. Published July 1988 (vol 100 no 7); exact day null. Superscripts rendered inline in quote.", "verbatim_quote": "TABLE 6. SUMMARY OF REGRESSION EQUATIONS TO PREDICT PEAK DISCHARGE ... 2. Landslide Q = 0.0158(PE)^0.41 12 0.81 185 ... Note: Q = peak discharge (m3/s); PE = potential energy (joules).", "sweep_ref": "sweep-2026-09-11/D_entries.json[30]" }, { "id": "E-111", "item": "Costa & Schuster (1988) definition of potential energy PE", "value": "PE = dam height (m) × lake volume (m³) × specific weight of water (9,800 N/m³)", "unit": "J", "source_url": "https://hydroschool.org/wp-content/uploads/2024/10/i0016-7606-100-7-1054.pdf", "publisher": "Costa & Schuster 1988, GSA Bulletin, p.1065", "published_date": "1988-07", "event_time": null, "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "specific weight fixed at 9,800 N/m³", "use": "narrative_only", "notes": "Uses DAM HEIGHT (not water depth or drawdown). Candidate ρ·g·h·V with ρ=1000, g=9.81 gives 9,810 N/m³ -> PE +0.10%, Q +0.04% vs original constant (negligible). V is stated as 'volume' of the lake (not released volume).", "verbatim_quote": "Potential energy of a lake behind a dam can be computed as the product of dam height (metres), volume (cubic metres), and specific weight of water (9,800 newtons/cubic metre).", "sweep_ref": "sweep-2026-09-11/D_entries.json[31]" }, { "id": "E-112", "item": "Costa & Schuster (1988) stated applicability / limits", "value": "Large scatter (SE 64-185%); regressions suggested for reconstructing past peaks; envelope for conservative rapid prediction; sediment bulking can increase peaks manyfold downstream", "unit": "qualitative", "source_url": "https://hydroschool.org/wp-content/uploads/2024/10/i0016-7606-100-7-1054.pdf", "publisher": "Costa & Schuster 1988, GSA Bulletin, pp.1065-1067", "published_date": "1988-07", "event_time": null, "accessed_date": "2026-09-11", "source_tier": "primary", "confidence": "High", "reported_precision_or_uncertainty": "n/a", "use": "narrative_only", "notes": "Also p.1065: 'The large scatter in the data in Figure 12 reflects the diverse characteristics of individual dams within each category'. p.1067: peak discharge 'may not attenuate but can actually increase manyfold by incorporation of easily erodible sediment and debris'. Figure 12 landslide data span roughly 10^8-10^16 J (read from plot, approximate). Predominant landslide-dam failure mechanism: overtopping (Table 7).", "verbatim_quote": "For reconstructing past flood peaks from the failure of natural dams for paleohydrological or sedimentological investigations, regression equations for different kinds of natural dams with potential energy as the independent variable could be used (Table 6).", "sweep_ref": "sweep-2026-09-11/D_entries.json[34]" }, { "id": "E-120", "item": "Rainfall role", "value": "not a regular rainfall flood; no heavy rainfall reported immediately before the event", "unit": null, "source_url": "https://kathmandupost.com/national/2026/08/26/scientists-suspect-ice-avalanche-triggered-bhotekoshi-flood", "publisher": "Kathmandu Post (reporting DHM)", "published_date": "2026-08-26", "event_time": "2026-08-26", "accessed_date": "2026-09-03", "source_tier": "secondary", "confidence": "Medium", "reported_precision_or_uncertainty": "qualitative", "use": "narrative_only", "notes": "Supports the sudden-release boundary condition used by every member; cannot discriminate between members. Carried from the 4 Sep 2026 evidence freeze; not re-fetched in the 11 Sep sweep.", "sweep_ref": null }, { "id": "E-121", "item": "Infrastructure exposure", "value": "buildings, bridges, highway and hydropower assets damaged", "unit": null, "source_url": "https://www.icimod.org/press-release/major-flash-flood-sweeps-through-nepals-rasuwa-district-raising-fears-of-further-downstream-flooding/", "publisher": "ICIMOD; USGS", "published_date": "2026-08-26", "event_time": "2026-08-26", "accessed_date": "2026-09-03", "source_tier": "near_primary", "confidence": "Qualitative", "reported_precision_or_uncertainty": "qualitative", "use": "narrative_only", "notes": "Carried from the 4 Sep 2026 evidence freeze; not re-fetched in the 11 Sep sweep.", "sweep_ref": null } ], "simulation_outputs": { "version": "sim-claude edff56c — cases/nepal_2026, outputs generated 2026-09-04; not re-run for this update", "outputs": { "SIM-ENS": "cases/nepal_2026/outputs/hydrograph_ensemble.json (member scenarios, source peaks water and bulked, wave volumes)", "SIM-ROUTE": "cases/nepal_2026/outputs/routing_summary.csv (per-member per-station arrival, peak, stage rise, 30-min rise)", "SIM-VAL": "cases/nepal_2026/outputs/validation.json (as-run 4 Sep scoring)", "SIM-INV": "cases/nepal_2026/outputs/inverse_estimate.json (Manning inversion at the reported rises)", "SIM-DIAG": "cases/nepal_2026/outputs/review_diagnostics.json, from scripts/06_review_diagnostics.py — read-only post-processing of the outputs above: volume/discharge types, arrival rule, stage-baseline defect, Costa & Schuster cross-check, timing checks against DHM telemetry, re-scored observational checks", "SIM-VIZ": "cases/nepal_2026/outputs/viz_data.json -> lhonak.goatai.io/nepal" } } }